Chapter 1: The Locked Room Era

The woman looked terribly excited, and she was ranting at me with such force that spittle was on the verge of flying. And to think, there were times she was so gloomy. I wondered if she was emotionally unstable.

According to her, she was a survivor of a mass suicide. She went to an abandoned house deep in the mountains with a group she'd met on a suicide website. There, they prepared a number of glasses of water equal to the number of members of their group. In the water, they dissolved cyanide, aconitine, or tetrodotoxin, except for one glass that simply contained a sleeping pill.

“Do you know what that means?” the woman asked. “It means only one of us would survive.”

That made sense to “me”.

“And I'm the one who took that pill.”

That also made sense to “me”.

“It's all such a mess,” she said. “We were all going to die together in peace, but here I am, still alive, drinking coffee in a shithole like this.”

“Isn't that good, though?” “I” asked. “Life is precious.”

The woman chuckled.

“You think so?”

I took a sip of my coffee. It was bad. Well, “I” did make it myself. Apparently, “I” was lousy at making coffee.

Or rather, there's only one thing “I” am good at.

That is... making locked rooms.

“Anyway, I survived,” the woman said. “That's why I came to see you.”

The woman pointed at “my” face.

“To see you, 'Locked Room User'.”

“Kasumi, you want some Pocky?”

As I sat looking out the window of the train, Yozuki Asahina, who was sitting across from me, suddenly held out a box of Pocky. “Sure”, I said and picked one out of the box offered to me. As I held it in my mouth, I looked back out the window. The December scenery flew by. The snow hadn't piled up yet, but the plants had withered. It was lonely. Somehow, I had a feeling of ennui.

“What, you're having a feeling of ennui?” Yozuki said while munching on a Pocky stick. “Are you trying to be a poet? Are you the type who writes down your own poems in a notebook every night before bed?”

Well, I could tell she was making fun of poets. I had to say something, or she'd never stop.

“I haven't written a poem since I was in middle school.”

“You wrote poems in middle school?”

“All middle school students write.”

“You wouldn't know what's normal. I'd like it if you stopped comparing your own standards to the world's, Kasumi.”

For some reason, that angered me. By the way, “Kasumi” is my first name, and my last is “Kuzushiro”. Kasumi Kuzushiro. When I was in elementary school, I was called “Kuzukasu” for a bit. It's like Kimutaku, except for the bits where it isn't, which is all of them. It ended when the teacher called a class meeting and scolded everyone, saying “Stop making fun of Kuzushiro”. That class meeting made me really sad. When I told Yozuki about it, she said “With 'Kuzu' and 'Kasumi', it's kind of like a seasonal word in a haiku.” I didn't really understand, but I think she was trying to cheer me up.

Yozuki is my childhood friend, 20 years old, in her second year of college, three years older than me in my second year of high school. Her hair is pale brown, shoulder-length, and fluffy, and her face is extremely normal. She liked to boast that she was once “scouted seven times in one day.” Mind you, four of those times were from cabaret clubs, and two were as hair models for beauty salons. “But the other one was for a proper entertainment agency”, she insists. “I was really happy for the offer. But unfortunately, I have the personality of a fickle cat. I'm not suited to jobs like show business where there are so many rules to follow.”

It's true that Yozuki is capricious as a cat, and she probably wouldn't last in the world of entertainment. Or rather, she can't hold down any job. Her special ability is to be fired from any part time job within a month.

The capricious cat used her smartphone while eating Pocky. Then she let out an “Ah!”

She stared intensely at her phone.

“Hey, Kasumi, it looks like there's been another locked room murder.”

“Eh, seriously?”

“Yeah, in Aomori. The locked room division of the prefectural police are working on it.”

I took out my smartphone and checked the news. Apparently she was serious. As usual, this country is flooded in locked room murders.

“Strange times we're living in, huh?” Yozuki mused while eating her Pocky.

I agreed completely. A single murder case had dramatically changed our world. Japan's first locked room murder was committed three years ago. Ever since, crime in this country has revolved around what happens behind closed doors.

Our destination was an unmanned station. Yozuki and I stretched on the empty platform. My joins popped. It had been three hours since I left home. Quite a trip.

“So, where will we be staying tonight?” I asked.

“Well,” Yozuki answered as she looked at her smartphone, “From here, we drive halfway up the mountain, then the road will end, so we'll have to walk from there.”

“The road cuts off midway?”

“Yeah. It's about an hour of walking.”

“You sure have to walk a lot.” Although that was probably good for your health.

The two of us walked through the ticket gate and went out to the roundabout in front of the station. We hailed a taxi there.

Yozuki told the taxi driver our destination.

“To the House of Snow, please.”

The House of Snow was currently being used as a hotel. The reason we were going there during winter vacation was because Yozuki visited my home about a month ago. She'd come to visit – that much was common for her. But that day, she looked like she had purpose. As she drank the coffee I'd made, she abruptly spoke.

“Kasumi, I think I'm going to go look for the yeti.”

Oh. So she'd finally lost it.

“...The yeti?”

“You don't know? It's a type of UMA (Unidentified Mysterious Animal). It's big and hairy and... you know, a yeti.”

No, I knew what a yeti was. The question was why she was looking for a yeti.

“You know, I really like UMA. I've been reading the occult magazine 'Mu' for as long as I can remember.”

Come to think of it, I did remember seeing her read that before.

I swallowed a sigh and took a sip of my coffee.

“Well, good luck with that,” I told her, forcing sincerity into my voice. “I'm sure it'll be tough to find the yeti, but I hope you make it back safely.”

Please don't let this be our last conversation. I can't bear the thought of losing my childhood friend to a yeti hunt.

Seeing me looking so depressed, Yozuki let out an exasperated sigh.

“What are you talking about, Kasumi? You're coming with me.”

I wondered what in the world she was talking about.

“...Are you asking me to accompany you to the Himalayas?”

Look, she's my friend, but there are still limits to what I'd do for her. Seeing the look of astonishment on my face, Yozuki explained.

“What are you talking about, Kasumi? We're only going to Saitama.”

Okay,now she'd lost it. 

I rubbed my eyes. Her confident face remained in place. Looked like she was serious. I hoped there was some sort of mistake.

I asked her straight.

“So, why are you going to Saitama to look for a yeti?”

“Well, obviously, because there's a yeti there.”

She said it as though I'd asked something obvious like “Are there mountains there?”

“...There's no way there's a yeti in Saitama.”

“Yes, there is. Because there's the Saitama Yeti.”

“The Saitama Yeti.”

It sounded more like the name of a soccer team.

“During the Ice Age, Japan and the continent were connected by a land bridge,” Yozuki explained, sounding proud of herself. “That's why it could have walked from the Himalayas to Japan.”

“So the yeti came to Saitama from the Himalayas during the Ice Age?”

“Yeah, it's possible.”

It really wasn't.

“So, Kasumi, let's go to Saitama and hunt for the yeti together,” Yozuki said, leaning towards me. “I'm sure it'll be a memory you'll never forget.”

That, we could agree on. I'd certainly never forget going to Saitama to look for a yeti.

 “...”

I thought about it for a while and came to my conclusion.

There was no way I was going.

Naturally, I turned her down. Then Yozuki clung to me and stared begging.

“Please, Kasumi, come with me! Are you really planning to force your precious childhood friend to travel alone?”

“No, you should go with your other friends.”

“What are you talking about? If I asked them to go to Saitama to look for a yeti, they'd never speak to me again!”

“I am astonished you still have that much common sense.”

I shook off Yozuki's clinging. She let out an “Ah!”, then sank to the floor. She took a deep breath.

“Please listen, Kasumi.”

“Alright.”

“This search for the yeti will definitely benefit you, too.”

I tilted my head suspiciously. “I get something out of this?” I asked. “Yes, you do,” Yozuki said, sitting down on the floor. “The advantage is that you don't need to pay.” That was rather old fashioned.

She held up an index finger and gave me a proud look.

“You won't believe this, the hotel we'll be staying at is the House of Snow.”

“The House of Snow?”

I tilted my head a bit. What was that? The name sounded familiar.

“Kasumi, you're a fan of Byakuya Yukishiro.”

“Ah, you mean that mansion!”

Seeing my sudden excitement, Yozuki relaxed and gave me a smug smile. Seeing that gross face kind of pissed me off. I coughed.

“I see. So you're planning to stay at the House of Snow?”

I forced myself to act calm, even though I was still excited.

Byakuya Yukishiro was a mystery novelist who was especially good at writing locked room mysteries. Although he'd passed away seven years ago, he was still a popular author who had many works prominently displayed in bookstores.

I was also a big fan. It was well established among fans that, while there was debate over whether his best work was “The Locked Room Village Murders” or “The Locked Room Mansion Murders”, his real masterpiece was something completely different. However, that wasn't a novel at all. It wasn't a TV drama, manga, or movie, either.

It was a real incident.

About ten years ago, Byakuya Yukishiro gathered writers and editors at his mansion for a house party. Delicious food, fine drinks, and Byakuya's own winning personality kept the party lively. But in the midst of all that, there was an incident.

It was a trivial incident, more of a prank than anything. It's not like anyone was hurt. However, a French doll was found in a room in the mansion, with a knife lodged in its chest.

And that room was a locked room. The door was locked from the inside, and the only key to the room was found inside. And that wasn't all. The key was inside a plastic bottle, and the lid was closed tight.

As a result, the room came to be known as the Locked Room in a Bottle.

From the moment the incident was found, Byakuya had a grin on his lips. Everyone who'd seen it was intrigued. He was the culprit of the incident, one of the events at his party: A murder mystery game set up by Byakuya, the host.

If that was the case, they'd accept his challenge.

Those present were all writers and editors in the same industry. Everyone had their own opinions on the locked room. The noisy debates they held eventually developed into an impromptu deduction competition.

Everyone at the party said they'd had fun. And they all added the same comment at the end: “It would have been even more fun if I'd been able to solve the mystery.”

The locked room went unsolved.

That was Byakuya Yukishiro's true masterpiece: The “House of Snow Locked Room Case”. Of course, it wasn't a criminal case, so it never went to trial, but it happened seven years before the first real locked room murder in Japan, three years ago.

A locked room that hadn't been solved in ten years.

It was still discussed among mystery fans today, and the House of Snow, where it had taken place, was a popular “I need to visit it at least once before I die” spot. The House of Snow had since fallen into the hands of a new owner and been renovated into a hotel, but I'd heard the Locked Room in a Bottle had been preserved exactly as it was back then. Apparently, there was even evidence of the trick left behind.

“...”

And Yozuki was using that as bait to get me to come with her. Call me weak, but I decided to accompany her. The House of Snow had a somewhat unusual rule that they would only accept long-term guests, specifically ones staying for at least a full week, which naturally meant that staying there was expensive. I don't know where Yozuki got the money, but if she could get me into the House of Snow for free, it would be too good to pass up. And while I was at it, maybe I would help her with a bit of yeti hunting, too.

After getting out of the taxi and walking for about an hour, I saw a bridge. It was a wooden suspension bridge, about 50 meters long. A deep valley cut through either side of the forest, and the wooden bridge connected the two sides of the valley. The depth to the bottom of the valley was about 60 meters. Both sides of the valley looked like completely sheer cliffs, making it impossible for a human to climb up or down.

Yozuki peered down to the valley below and let out an “Uwah” noise.

“If you fell down there, you'd definitely die.”

Yozuki enjoyed saying things that were obvious. But it was true if we fell we would die, so crossing the bridge was scary. After crossing the suspension bridge and walking for five more minutes, we saw a white wall appear over the horizon. It was a high wall, probably about 20 meters.

In the center of the wall was a gate. It was open, so we went through. Near the gate was a surveillance camera, which captured the entrance of we guests.

Right... we were guests. Inside the wall was a garden, and in the center of the garden was the hotel. A chalk-colored Western style building, noticeably whiter than the white walls. As the name suggested, the House of Snow was the color of fresh fallen snow.

The garden surrounding the wall was also large – It gave the impression of being more of another wall around the mansion than a garden. There were few trees in the garden, the ground was bare black soil, and there were no flower beds of any kind.

As we approached the building, I saw a blonde woman wearing a maid's uniform, smoking a cigarette. She was around 20 years old, and her shoulder length hair looked dyed, not natural. She was pretty despite her lack of makeup, and gave the impression that she was rather carefree. When the maid noticed us, she took a portable ashtray from her pocket and put out her cigarette. She looked regretful to leave it behind.

“Do you have a reservation?”

Her tone was curt. “Yes, I have a reservation for Asahina”, Yozuki said. The maid nodded.

“We've been waiting for you. Please come inside.”

The maid's tone made me wonder if she really had been waiting for us. For a maid, she lacked the spirit of service. Well, it might have been more of an issue of motivation that personality.

We went through the front door and into the House of Snow. As we walked down the short hallway coming off the entrance, the maid spoke as if suddenly remembering.

“I'm Chika Meirozaka, and I work as a maid at this hotel. If you need anything, please come to me about it.”

She rattled it off without emotion. Her tone was completely businesslike, which made me wonder if it really was okay to ask her.

“Meirozaka, huh?” I heard Yozuki mutter. “Meirozaka the Mei-d.” Apparently, it was a play on words. Yozuki had a habit of making puns to remember people's names by.

After passing through the short hallway coming from the entrance, we arrived in a lobby. It was so spacious that it was hard to believe this had once been a private residence. It was the size of a lobby from a medium sized hotel. Several tables and couches had been set up, where several customers enjoyed coffee and tea. There was also a plate of cake on a table, so it appeared they also served the sorts of light fare you'd find in a coffee shop. A large TV was attached to a wall.

Yozuki and I decided to check in at the front desk. The woman at the front desk was about 30 and had short hair. She wore a black apron over her sweater, making her look even more like a coffee shop owner. She had the air of a calm adult, like the sort of beautiful female store owner who would solve everyday life mysteries if you brought them to her.

But in reality, it seemed she was the manager of this hotel. Apparently, she and Miss Meirozaka the maid ran the whole place by themselves.

Her name was Reiko Shihai. “Shihai the shihainin (manager)” Yozuki muttered without hesitation.

Ms. Shihai gave us a soft smile.

“Ms. Asahina, Mr. Kuzushiro, welcome to the House of Snow. We look forward to serving you rich nature, delicious food, and a chance to to solve the locked room left behind by the great author, Byakuya Yukishiro. We, the staff of the House of Snow, will do everything in our power to accommodate you.”

Ms. Shihai sounded a bit embarrassed to say so, then she turned and started tapping on the keyboard of the front desk's computer. I guess she was confirming our room numbers. “Both of you will be staying on the second floor of the west building. Ms. Asahina will be in room 204, and Mr. Kuzushiro in room 205.”

She retreated to a room behind the front desk, then returned with two keys in hand. They were silver keys about 10 centimeters in length. They were slender and had their room numbers engraved on the handles. She handed a key to me and another to Yozuki.

As we checked the keys we'd received, Ms. Shihai spoke in a joking voice.

“Please don't lose them, we don't have any spares.”

When she said that, I took another look at the key. The tip had a rather complicated shape. It probably wasn't possible to make a duplicate.

I put my key in my pocket. Then I whispered “Room 205” to myself and asked Ms. Shihai a question.

“Um, what do you mean the west building?”

My room was “room 205 in the west building”, but since this was my first time here, and I'd only taken a brief look at the exterior, I didn't really understand the structure of the building.

“Forgive me, sir. Please check this panel here.”

Ms. Shihai said that and pointed to a panel decorating the wall behind the front desk. It showed an overhead view of the building. It looked like a floor plan of the House of Snow.

“The House of Snow consists of four buildings,” Ms. Shihai explained. “First is the building we are currently in, the central building. There is a dining building to the north. As the name suggests, this is the building where the dining hall is located. Breakfast, lunch, and dinner are all served there.”

According to the floor plan, the east, west, and dining (north) buildings were all connected to the central building where the lobby was located by doors and corridors, but conversely, the three buildings to the east, west, and north weren't connected to each other. It seemed to move from one building to another, you would have to pass through the central building. For example, to move from the west building to the east building, you would have to pass through the lobby.

“Your understanding is correct,” Ms. Shihai said with a soft laugh. “You could say the central building is a joint, connecting the other three buildings. Additionally, this House of Snow has no back door. All of the windows either do not open, or have lattices that prevent them from being used to enter or leave the building. The only way to access the garden is through the front entrance in the central building, but as I mentioned earlier, there are no other entrances, so there is no way to move through the garden to enter the other buildings.”

“Hmm, that's so inconvenient,” Yozuki said. “Why is it designed like that?”

“Well, I can't explain how a mystery novelist thinks,” Ms. Shihai said with a vague smile before pointing at the floor plan again. “By the way, the connecting corridors joining each building have walls and a roof. They aren't exposed to outside air, so you can't go out that way, either.”

I nodded at Ms. Shihai's words. In other words, even though they were connected separate buildings, they weren't actually any different from a hallway you'd find indoors.

I looked at the floor plan again, then asked something.

“What's this building here?” In addition to the four main buildings, there was one other visible on the floor plan. It was a small building jutting out of the top of the west building. It seemed to be connected by another corridor.

“Ah, that's a detached room,” said Ms. Shihai. “It's one of the rooms Byakuya Yukishiro used to write in. It's also called the Canned Food Room. Whenever he had trouble coming up with ideas, he would isolate himself in that room and take a bite of an apple.”

“Why an apple?” asked Yozuki.

“It's from an Agatha Christie story,” I explained. It was said that biting an apple while soaking in the bath would cause good ideas to come to you. Every time I heard that, I wondered if it was actually true.

At any rate, that was Byakuya Yukishiro's Canned Food Room. I definitely wanted to see that.

“Unfortunately, it is currently being used as a guest room, so I cannot show it to you,” Ms. Shihai said apologetically. “It has already been reserved for today.”

Ah, that was a shame. Incidentally, the detached room was also connected by a corridor, so you'd have to go through the west building to get there.

“Well then, please enjoy your stay.” After checking in at the front desk, we were guided to our rooms by Miss Meirozaka the maid. The west building was three stories tall, and my room, room 205, was in the very back of the second floor. Five rooms, from 201 to 205, were lined up in a straight hallway. After leading me to the front of the room, Miss Meirozaka bowed deeply. “Meals will be served at 7:00 P.M., so please come to the dining room at that time. Ms. Shihai and I have rooms here in the west building, so if you need anything in the middle of the night, please let us know.”

Miss Meirozaka recited that in her usual flat tone. Was it really okay to make a request to her? I was getting a little anxious.

With a groan, I put a hand on the knob and opened the door. Inside, I saw a clean room decorated in white. It was so clean it was hard to believe the building only had two employees.

“Well, we have about 20 Roombas,” Miss Meirozaka said, peeking into the room from behind me, “So I leave most of the cleaning to them. Of course, there are some small details that require a human touch, but I can handle them. I might be like this, but I'm good at cleaning.”

“Is that so?” I was a bit surprised.

“Yes, I was a finalist in the World Maid Cleaning Championship.”

“World Maid Cleaning Championship Finalist.”

A mysterious title had appeared. It was probably a joke, but for all I knew it might have been true.

“Well, enjoy your stay.”

Miss Meirozaka said that again and went back towards the lobby. After putting down my bags, I decided to take a look around the room.

The room was about 10 tatami mats in size, with a separate toilet, bath, and a large washroom. The only furniture was the bed, a TV, and a two-tiered refrigerator with a freezer. The floor was the color of amber, and the window didn't open. It was pretty nice. According to Miss Meirozaka, this was originally a guest room. Byakuya Yukishiro had liked to invite guests, so most of the rooms in the west building were guest rooms.

I decided to check the door next.

A single door the color of a chocolate bar. Contrary to its solid appearance, it was light. It appeared to be a flush door with a hollow interior, the sort often used in interior doors in houses. Since it was made of wood, it probably weighed around 10 kilograms. An adult could probably break it in a few hits. Also, I'd heard from Miss Meirozaka that all the doors in the west building were the same. That went for their design, size, and even whether they opened inwards or outwards. In other words, if you knew the structure of the door to your own room, you knew the structure of the doors to all the rooms. Incidentally, the door opened inwards. Therefore, all the doors in the west building opened inwards.

I was getting excited. I got down on the floor and peeked under the door. The door and its frame fit tightly together, leaving no gaps. The vaunted “No gap under the door” type door. That meant it was impossible to use the classic locked room trick of returning the key to the locked room through the gap in the door. As a mystery fanatic, that made me smile.

After I finished checking the door, I decided to leave the room. I'd promised Yozuki we'd have tea together in the lobby. I went next door to room 204. When I knocked, Yozuki said “I'm sorry” and stepped outside.

“I'm not done unpacking yet. Just go on ahead.”

That was an obvious lie. Yozuki's loose, fluffy hair was falling onto her face. Apparently, she'd been asleep. She probably needed time to clean herself up.

As I stood looking at her bedhead, Yozuki combed her hair with her hand, looking embarrassed.

I had no choice but to head to the lobby alone. As I descended the stairs to the first floor of the west building, I saw her. A girl was quietly looking out the window of the hallway into the garden. She had white skin and silver hair cut close to the shoulders. I could tell at a glance she was a foreigner. Moreover, she was as picturesque as a doll.

Was she about my age? She looked like a high school student.

When the girl noticed me, she smiled at me. She said “Hello” in fluent Japanese. I hurried replied with a “Hello” of my own. I always get nervous talking to foreigners.

The girl, in contrast, didn't show any signs of nerves. “This is a nice place,” she said with a smile, striking up some small talk. “This must make a nice summer getaway.”

Summer getaway was a pretty difficult bit of Japanese. This girl knew some hard words.

“Did you come here for sightseeing?” I asked, trying to keep up the small talk. The girl replied “Yes, I am sightseeing. I heard there are skyfish near here.”

“Skyfish?” I tilted my head. The girl held up her index finger as she explained.

“The skyfish is a flying fish. Simply put, it's a UMA.”

“Simply put, it's a UMA.”

Those words froze me in place.

...This girl was the same as Yozuki.

The sudden Yozukian declaration made me hesitate. But after giving it some thought, I said “Skyfish are wonderful, aren't they? I've always dreamed of seeing a fish fly through the sky.” My motive for saying such an opportunistic thing was purely the desire to be liked by a cute girl.

And thanks to my efforts, the girl did smile happily. “Skyfish are wonderful,” she said shyly. “I came all the way from Fukuoka because I wanted to see one.”

“Fukuoka? You aren't from overseas?”

“I'm a British citizen living in Fukuoka. I've lived here since I was five years old.”

I see, no wonder she was so good at Japanese.

After talking with her for a while, I decided to head to the lobby. “See you later”, I said with a bow, a gesture she returned. And just before we parted, she told me her name.

“My name is Fenrir Alicehazard. I'm planning to stay here for a while longer, so let's look for the skyfish together.”

I gave her a thumbs up.

“I'm Kasumi Kuzushiro. Please join me in skyfishing.”

“Oh my gosh, Kasumi, I can't get internet out here,” Yozuki's pained voice came from the seat across from me between sips of her melon soda. I had just sat down on one of the couches in the lobby and taken a sip of tea.

“You showed out of range from the moment we got off the taxi, right?”

“Yeah, but I thought I'd be able to use the wi-fi once we were in the hotel,” Yozuki lamented. Then she stopped Miss Meirozaka the maid, who was wiping the table beside us with a cloth. 

“Excuse me, is there no wi-fi here?”

“Sorry,” Miss Meirozaka said apologetically. “We have internet, but there's no wireless LAN installed. Cell phones will always show as out of range.”

“Ugh, seriously? It's like a deserted island,” Yozuki groaned as she put her smartphone back in her pocket. Then she looked around the lobby. There were a few other guests there.

“How many guests are staying here tonight?”

“There are twelve customers with reservations.”

“Eh, twelve? That's a lot.” Yozuki's eyes went wide. Then she grew a look of satisfaction. “I guess everyone's interested in the yeti.”

“Yeti?”

“Please ignore her,” I asked Miss Meirozaka.

After Miss Meirozaka tilted her head at us, she told us why the hotel was thriving.

“The manager's cooking is a bit flashy, but it's really delicious.”

“Ms. Shihai?” said Yozuki. “Does she do the cooking herself?”

“Yeah, it's a creative Italian-style cuisine with a widespread reputation for good taste. The reason why we only accept long-term guests is because of Shihai's selfish desire to have her customers taste all sorts of different dishes. But it's worth it, and there are plenty of customers who come here just for the food. Mr. Yashiro over there, for example.”

Miss Meirozaka turned her attention to a man chatting away at a table a bit away from us. A man in his 40s wearing an expensive suit was talking to a man in his 30s in jeans and a sweater. The man named Yashiro appeared to be the 40-something.

“By the way, Mr. Yashiro is the president of a company.”

“He's the president of a yashiro (company)” said Yozuki.

“He seems to really like the food here, so he's a regular guest. Well, I think he's really just trying to seduce the manager.”

If she said so, I had no choice but to believe it. The president was the effortlessly confident type, with shining eyes. He looked like a womanizer.

“Is that other person accompanying Mr. Yashiro?” asked Yozuki. She was looking at the man in the sweater accompanying Yashiro. In contrast to Yashiro, his appearance was calm.

“No, it looks like those two just met for the first time here,” Miss Meirozaka said. “It seems they both collect watches as a hobby, and they started talking as soon as they saw each other's watches. They've both been staying here since yesterday, and they've become that close in only a day.”

Indeed, the atmosphere around them didn't seem like they'd only known each other for a day. But to think he was wearing a watch that would catch the eye of a company president... I wondered if the man in the sweater was actually wealthy.

“Yeah, he's a doctor.”

“A doctor?” I guess he was from the upper class after all.

“Yes, I hear his name is Dr. Ishikawa.”

“Ishi (doctor) Ishikawa” said Yozuki.

“I hear they're both wearing watches that cost millions of yen. Personally, I think luxury items like that are just the worst.”

Miss Meirozaka spewed poison like it was nothing. She was a venomous maid. Moreover, thinking about it, she was sharing personal information like her guests' occupations. She may have also been a loose-lipped maid. She was fun to talk to, but I couldn't say she was a good employee.

The maid who didn't care about people's personal information bowed to us and went to leave. I suddenly remembered what I had to ask her. When I stopped her, Ms. Meirozaka looked at me with annoyance.

“What is it?”

“No, it's just...” I took a sip of tea to wet my throat. “I heard that there's a room in this mansion that hasn't been touched since it once belonged to Byakuya Yukishiro.”

Despite my vague words, Miss Meirozaka seemed to understand me. “Oh, you're looking for that room,” she said.

“The scene of that 'House of Snow Locked Room Case'.”

I gave a nervous nod. It was the scene of the incident that had occurred at Byakuya Yukishiro's house party.

Miss Meirozaka gave a shrug of her shoulders.

“I don't get what's so interesting about solving a locked room mystery, but of course I can show you. It's a specialty of the hotel, alongside the manager's Italian food.”

I finished my tea and stood up. Then she asked about Yozuki, who was still drinking melon soda.

“What about Yozuki?”

“Not interested.”

She replied instantly. I was suddenly very lonely.

The “House of Snow Locked Room Case” occurred on the second floor of the east building, which was located on the opposite end of the manor from the west building where I was staying. The hallway on the second floor of the east building had a long pile carpet that felt fluffy under my feet. Miss Meirozaka, who was walking in front of me, suddenly stopped and pointed to a door.

“That's the room,” Miss Meirozaka said.

That was the room... I gulped.

Feeling a little nervous, I grabbed the knob and opened the door. The room was about the same size as my room in the west building, 10 tatami mats, but it had another room connected to it. There was another door on the wall to the left viewed from the entrance to the room. And that room was the real scene of the “House of Snow Locked Room Case”.

I entered the room and went through the door on the left wall. The door was open. From what I'd heard, it had been open at the time of the incident ten years ago, too.

When I stepped into the next room, my eyes fell on a toy. Not a French doll with a knife stuck in it, but a teddy bear, uninjured. Of course, it would be a shock to the guests to see a humanoid with a knife in its chest, so it seemed this had been left here instead.

I tried to remember the outline of the incident I'd read in the past. The outline went like this:

Ten years ago, Byakuya Yukishiro held a party at his mansion. While everyone was enjoying a meal in the living room of the central building (currently renovated into the lobby), a woman's scream came from the east building. Surprised, everyone followed the scream to the east building. Then they heard another scream. Apparently, it was coming from the second floor. They climbed the stairs, and as they ran into hallway, they heard a third scream. That was when they realized which room the screams were coming from. They grabbed the doorknob and turned it. It was locked. One of the guests, a mystery writer who'd debuted around the same time as Byakuya, asked him the obvious question.

“Where is the key to this room?”

“It's been missing for a few days now,” Byakuya answered. “I don't know where it went. But it's strange. This room wasn't locked when I checked yesterday...”

“Then someone locked this door?”

“That seems to be the only conclusion.”

Another visitor asked. This one was a young editor from a major publishing company.

“Don't you have the master key?”

“I don't,” Byakuya shook his head.

 “Yes you do, I've seen you use the master key before.”

“Ah, that's the master key to the west building. The key systems are different between the east and west buildings. The master key to the west building can't unlock the doors in the east building. There's no master key to this door.”

“Why not?”

“Why isn't there? I forgot.”

Byakuya spoke lazily. Another guest questioned him. This was a teenage girl who'd recently debuted as a young author.

“Then isn't there a spare key?”

“There are no other keys. All the keys in the House of Snow are extremely special. It's impossible to make any duplicates.”

“Then the only way in is to break the window.”

“No, there's a lattice over the window, so that isn't a way in or out.”

“Then, how on Earth can we get inside...?”

Then, they heard the woman's scream again. They all looked at each other. “Can't be helped,” said another guest. He was a man in his 30s, a literary critic known for his harshness.

“Let's break the door down. Is that alright, sir?”

“It is an emergency.”

Byakuya reluctantly nodded.

The strongest of the men took up position in front of the door that opened inward. Then, with a united cry, they rammed the door. They heard it creak. Repeat that a few times. On their tenth charge, they finally heard the door crack.

The broken door swung open. The room was pitch black. Someone fumbled to turn on a light.

In the lit room, they could see no abnormalities.

“Maybe it came from over there,” said the young editor from the major publishing company. What he was pointing at was the door to the left as seen from the entrance. That door, which went to the next room, was currently open. The door was right of center on the wall, that is to say, at the back of the room when viewed from the entrance.

Everyone cautiously approached the door to the next room. The lighting in the adjacent room seemed to be linked to the lighting of the main room, where the entrance was located. By turning on the lights in the main room, the lights in the adjacent room also turned on. So when they approached the door, they could all clearly see what was inside. In the next room lay a French doll with a knife stuck in its chest. It was right in front of the door. The knife that had been thrust into the doll, looking like it had pierced through to the floor, had a blade about 30 cm long, shining brightly as it pointed towards the door.

No one screamed, but everyone looked surprised.

In the room, alongside the French doll, two more distinctive items were found. You could call them relics of the incident.

The first was a voice recorder. It had fallen next to the French doll. When they played it back, they heard a woman's scream. Apparently, the screams from earlier had come from there.

The second was a bottle that had fallen a bit further away from the French doll that played the role of “victim”. Inside the bottle was a key. Byakuya picked up the clear plastic bottle and said “It's definitely the key to this room.”

Everyone broke into a commotion.

“Then, that means this room is...” said the mystery writer near Byakuya's age. “Do you mean this is a locked room?”

“It's hard to believe,” said Byakuya. “Something like that won't happen in real life.”

“No, that isn't possible. Sir, let me have that key for a moment.” The famously harsh critic in his 30s took the bottle with the key from Byakuya. He opened the tightly closed lid and took out the room key from inside. “This key could be fake. It's a common trick.”

After saying that, he took the key and went back to the entrance of the room. Then he inserted the key into the keyhole and his eyes widened in surprise.

“It's the real key,” muttered the famously harsh critic in his 30s.

 “I can't believe it,” said Byakuya. “I never expected something like this to happen.”

“Hey, sir?”

“Yes?”

“Sir, what have you been grinning about this whole time?”

That was the teen girl writer who'd just debuted.

Everyone's eyes turned to Byakuya. The smile disappeared from his face and he spoke coyly.

“I'm not smiling.”

“Yes you are! No matter how you look at it, you're totally smiling. Ah, sir, could it be...”

The teenage female writer chose that moment to stop talking. She decided not to tell everyone what was going on. There would be time to hang this old man out to dry after she'd solved the locked room mystery.

She gave Byakuya a defiant smile, her own personal declaration of war. She wasn't the only one. The mystery writer Byakuya's age, the young editor from the major publishing company, the famously harsh critic in his 30s, and the other guests... They all felt the same.

I'll be the first to solve the mystery, and I'll show this old man up!

Thus, the locked room event at the house party – the mystery of the “House of Snow Locked Room Case” – had begun. Various theories were thrown around all night long, but nobody was able to find the truth.

“...”

That was the summary of the “House of Snow Locked Room Incident” I'd read in a book. The incident was written up at the end of a short story collection by the teenage female author present at the scene (that author was now in her 20s and was the proud owner of several major literary awards). I'd read it so many times that I could recite it from memory.

I took a deep breath and went straight to investigating. First, check the window. The window was located in the adjacent room, right across from the door connecting to main and adjacent rooms. It was a large window, reaching from the floor to the ceiling. As I'd heard, it was fitted with a metal lattice. The window slid open and was apparently open at the time of the incident, but due to the lattice, no one could go in or out through it.

After checking the window, I decided to examine the most important item from the incident, the key in the bottle. I picked up the bottle from the floor.

The bottle was smaller than I'd expected, about the size of a film canister. The lid was made of metal, like a jam jar's, and had to be twisted open. Of course, the lid was closed tight at the time of the incident. A small O-shaped protrusion was attached to the top of the lid. It looked like a string could be threaded through it.

After looking at the protrusion for a while, I turned my attention to the key inside the transparent plastic. “That's the key to this room,” said Miss Meirozaka, who'd been standing next to me for a while now. “It's the real one, not a replica. Please try not to lose it.”

The key was much smaller than the keys to the western building where I was staying. It was about 5 cm long. It was small enough to fit into the plastic bottle left at the scene. However, it was still too big to pass through the square grid of the window lattice. The size of the grid was much smaller than the key inside the bottle. In other words, there was no way to get the key into the room through the lattice. However, if it couldn't have come from somewhere else...

“I see,” I whispered. “What is it? What do you see?” asked Miss Meirozaka.

I went to the entrance of the room with the small bottle still in hand. Miss Meirozaka followed me. We both stepped back into the hallway, and I closed the door and knelt down on the pile carpet. I crouched down and looked at the bottom of the door.

“...What are you doing?” Miss Meirozaka asked me suspiciously. “I'm checking the gap under the door,” I replied.

 

 

 

 There was a gap under the door. There wasn't a gap like that in the room I was staying in, but this room in the east building seemed to have been built differently. However, I'd known this beforehand. It was in the write up in the book.

When I explained that to her, Miss Meirozaka said “To be precise...” and explained the layout of the doors.

“Only the room doors on the second and third floor of the east building have gaps under their doors. The east building is three stories tall, but only the rooms on the first floor have no gaps under their doors.”

“Why aren't there any gaps on the first floor?”

“Because the first floor has no carpet.”

I tilted my head, but after a moment, I realized what she meant.

“So it's to make sure the carpet doesn't get caught in the door?”

Miss Meirozaka nodded. I thought for a moment, then looked back at the door.

The door to this room opened inward, and the room's floor was covered in a long, shaggy carpet just like the one in the hall. The carpet in the hallway had a length of about seven centimeters, and the carpet in the room was about one centimeter. I could probably assume that the third floor, the uppermost floor, had the same specifications. Therefore, if there weren't a gap under the door, the carpet would get caught when the door opened, and the door wouldn't be able to open or close properly.

And this gap under the door was vital to the locked room. Although it was almost hidden from view by the tall carpet in the hallway, there was definitely a gap there. The conclusion to be drawn, therefore, was...

I took the key to the room out of the plastic bottle. I put it through the gap under the door. It was the right size and fit through easily. After locking the door with the key, it would be possible to put the key back in the room through the gap. Then, the next thing I had to check was...

I put the key back in the bottle and closed the lid. Then I tried to put the bottle under the gap in the door.

It got caught with a clicking sound. The bottle was too large to fit under the gap in the door.

“Uuwah.”

I heard Miss Meirozaka yawn. I was very sad.

Alright, there must have been another way... I looked more closely at the door. There was no thumb turn on the inside of the door; instead, there were keyholes on both sides. In other words, you needed the key to lock the door, whether you were inside the room or outside. That ruled out tricks like turning the thumb turn with thread.

In other words, the only way to create the locked room was to lock the door with the key from the outside.

“...The problem is, how do we get the key back in the room?”

“Well, if we knew that, there wouldn't be a problem, now would there?”

Interrupted by a sudden, unfamiliar voice, I turned my head. 

There was a man standing there. He was dressed in an old-fashioned suit, the sort the British wore in the prewar era. He was in his mid-twenties and stood about the same height as myself. And he was quite handsome. His face was chiseled, with short, waxed hair and a well defined forehead.

“Mr. Sagurioka,” said Miss Meirozaka. Then she sighed in frustration. “You're still here? I thought you went back to your room.”

“No, I was just going to the bathroom,” the man called Sagurioka said. “I needed a change of scenery. After all, if you just sit and think, you'll get stuck in the mud that forms in your thoughts and be unable to move.”

From their conversation, I got an idea of what was going on.

This man called Sagurioka was probably a customer. Of course, he had to be a guest at the hotel, but that's not what I mean by “customer”. Like me, Sagurioka was someone trying to solve the mystery of the House of Snow Locked Room Case. He'd started his investigation before me.

“You're right,” Sagurioka said as though reading my thoughts. “I'm also challenging this locked room. Ah, forgive my discourtesy – This is the kind of person I am.”

Sagurioka pulled a business card from his pocket and handed it to me. It read “Locked Room Detective Eiji Sagurioka”. Locked room detective... This man was a locked room detective?

Locked room detective is a new profession created in response to the locked room boom in this country. Currently, 30% of locked room murders committed in Japan involve the simplest of simple tricks, like using string to turn the key in the inside lock or hiding inside the room. The remaining 70% are more complicated or involve new, cutting-edge tricks and can't be handled by ordinary police officers. Therefore, the police ask outsider detectives to solve the mystery. The detectives assigned to the cases are called locked room detectives. They're people paid by the state to solve locked room mysteries.

However, only some locked room detectives are ever actually asked for help by the police, and most detectives can't make a living only solving locked room mysteries, so they wind up making ends meet by catching cheating spouses and finding lost dogs.

Sagurioka appeared to notice my suspicious look and shrugged his shoulders.

“Oi, oi, don't look at me like that. I'll have you know I once ranked in the top ten in 'This Locked Room Detective is Amazing!'.”

“Whoa, really? That's amazing!”

That changed my mind. “This Locked Room Detective Is Amazing!” is a magazine published twice a year, and as the name suggests, it lists the top ten locked room detectives based on their case results. Being listed anywhere in the top ten is an honor.

I read every issue on release, so I must have known about him already. I searched my memory. Eiji Sagurioka... it certainly sounded familiar. What had I read?

However, when I finally remembered the article where I'd seen Sagurioka's name, it wasn't from “This Locked Room Detective Is Amazing!”.

“...Mr. Sagurioka, were you involved in an extramarital affair recently?”

“Oh, don't worry about that.”

His response was immediate. He showed me a troubled smile.

I believe it was about a year ago that an article appeared in a weekly magazine. A young detective who'd made the “This Locked Room Detective Is Amazing!” top ten list was having an affair with a married woman. I remember being surprised at the time, thinking “Times really have changed. I never though a detective's infidelity would be reported in the papers.”

“It's a bitter memory, no doubt,” Sagurioka said with a shrug. “Well, even detectives have our weaknesses. I'm good at solving cases, but I'm less good at solving the mysteries of the heart.

Sagurioka said something cool. Well, maybe more lukewarm.

He coughed.

“Well, anyway, I'm a locked room detective, and I'm here for a magazine interview. I'm not here because of any affair, okay? It's a mystery magazine, and the plan is for me to be interviewed at the scene of the House of Snow Locked Room Case. Of course, I'm going to try to solve the case, but I don't think the reporters have even arrived yet. I'm just doing some preliminary research. Wouldn't it be cool if I could solve it?”

He was surprisingly down to earth. I asked Sagurioka something.

“So... How far have you gotten?”

“Honestly, I'm stumped,” Sagurioka said with a shrug. “As you just saw, the key can't fit under the gap in the door while it's in the bottle. So the culprit – that is, Byakuya Yukishiro – didn't put the key in the bottle then put in in the locked room, he put the key in the locked room then put it in the bottle.”

“Ah, I guessed that was it,” I said. “So he slid the key under the door, then used fishing line or something to move it to the next room and got it in the bottle somehow.”

“Oh, so you get it, young man.” Sagurioka whistled in admiration. “Therefore, the two remaining problems here are 1: How did he get the key into the bottle, and 2: how did he close the bottle?”

“I think 1 is possible if you try hard enough, but 2 seems pretty difficult.”

“I agree. I thought about wrapping fishing line around the lid and screwing it shut that way, but the bottle wasn't fixed to the floor... so it would be difficult as a matter of simple physics. So, how on Earth did he close the lid?”

“Then what about something like this? The bottle, with its lid open, was placed on its side inside the room, right next to the door. Then, from the corridor side, the culprit flicked the key under the door, hard. That launched the key into the bottle. From there, they used a thin stick or something to close the lid through the gap under the door.”

“From there, all he'd have to do is move the bottle to the next room,” Sagurioka nodded. “And luckily, the bottle's lid already has that O-shaped protrusion. If you hooked a thread on it and pulled, you could definitely move the bottle. But unfortunately, that trick is impossible. As you can see, the gap under the door is quite narrow. It's only about a centimeter. You can't close the lid with wire or anything with that little room to maneuver. More importantly, the lid was closed tight. It would be impossible to close it that tight with anything other than a human hand.”

“Then how in the world did he do it?”

“That's the mystery. Byakuya Yukishiro prepared an outrageous impossible crime.”

Miss Meirozaka stared at us with cold eyes the whole time. Eventually, she sighed, said “You two enjoy yourselves”, and left us.

Incidentally, the report on the “House of Snow Locked Room Case” compiled by the teenage female author present at the scene ends with this line from Byakuya Yukishiro: Even when dawn came and the deduction competition ended, Byakuya never admitted to being the culprit. All he said to the female writer was:

“What a shame.”

With that, you now have enough information to solve the mystery behind the locked room.

Two hours later, finally overcome by the mystery of the locked room, Sagurioka and I wandered our way back to the lobby. Sagurioka said “I'll see you later,” then made his way to a seat by the window. He looked tired. Well, I was tired, too.

Yozuki was sitting near the front desk, so I joined her. She was playing a game on her phone, but she looked up when she noticed me.

“So? How's the hunt for the truth behind the locked room going?”

“Honestly, I'm clueless.”

“Yeah, I saw that coming.”

And she looked back down at her phone. I was infuriated, but there wasn't anything I could say to that. I ordered a banana juice from Miss Meirozaka, then sat on the couch and shut my eyes. I was tired. My body felt like it was made of mud. I wanted to fall asleep, just like that...

But before I could, Yozuki kicked me in the shin. I ignored it, thinking she'd just accidentally bumped me with her foot, but then she did it again, as hard as she could. That couldn't have been a mistake. What a terrible woman.

When I opened my eyes, I saw Yozuki's face, looking innocent as could be. For some reason, she started whispering in a frantic, high-pitched voice.

“Kasumi! Kasumi!”

“What? What is it?”

“Look over there.”

Yozuki pointed towards the front. A man and a woman were standing there. They appeared to be guests. The man was in his late 20s and the girl was in her mid teens. They definitely weren't a couple. The man in glasses looked plain and dreary, while the girl was radiant. Her brown hair was tied in twintails, and although her face was young, she was eye-catchingly gorgeous. She had an aura about her. I felt like I'd seen her somewhere before.

“That's Riria Hasemi, the morning drama actress.”

“Wha-!?”

I reflexively raised my voice. Riria's eyes turned to me. I panicked and looked away.

Riria... Riria Hasemi. She was a nationally famous actress who'd starred in the morning drama that aired until autumn. I think she was fifteen years old. She was already popular, but that drama sent her to the stars, and now she was in demand for every TV show and variety program.

Naturally, Yozuki and I, being the two most normal people on Earth, were thrilled to see her.

“Hey, hey, Kasumi, no matter how you look at it, that's really her, right?”

“Yeah, that's definitely her.”

“She's so cute!”

“I know, right?”

“Can we get an autograph later?”

“Won't that make her mad?”

“She's a celebrity, she's gotta be used to this kinda thing by now, right?”

“Probably.”

“But then we'd have to pay for it, wouldn't we?”

We kept talking in whispers, never taking our eyes off of Riria. Riria got her key from the manager, Ms. Shihai. When she saw the room number engraved on her key, she suddenly squealed with joy.

“Wow, I got room 001! That's the detached building, right?”

“Yes, that's the separate space attached to the western building. Byakuya Yukishiro once used it as a writing room.”

“Wow, he did! I'm, like, totes a mega-super-fan of Mr. Yukishiro, so I wanted to stay there at least once.”

Riria was a fan of Byakuya Yukishiro? That was a surprise. And seeing her in person, she was surprisingly energetic. No, wait, I remembered seeing her act like this on variety shows and things like that.

“Hooray! Thanks a million! I'm so excited.” Riria happily grabbed her key and thanked Ms. Shihai. Then she huffed, her smile instantly vanished, and she yelled at the man accompanying her.

“Manei! Bring my bag to my room.”

The voice was surprisingly cold. The man called Manei said “Yes, Miss Riria,” and disappeared in the direction of the west building, carrying a brand-name travel bag (probably Riria's) with him.

Riria smiled at Ms. Shihai again.

“Can I get a drink here in the lobby? I'm, like, soooooo~ thirsty.”

“Yes, you can ask the maid over there for anything you need.”

“Really? Hooray! Excuse me, Miss Maid, can I place an order?”

Riria ran off towards Miss Meirozaka with a smile on her face.

And I thought Yozuki had mood swings... Mr. Manei was probably Riria's manager. Seeing her treat him so coldly, I thought that maybe celebrities were frightening.

“It must be tough for Mr. Manei. He's just a humble Manei-ger.” Even worse, Yozuki was making puns again.

Miss Meirozaka delivered the banana juice I'd ordered earlier, and I took a sip. As I absently glanced around the lobby, I noticed there were a fair number of people gathered there. President Yashiro and Dr. Ishikawa were still talking about watches, and the morning drama actress Riria was happily downing a grapefruit juice. Detective Sagurioka was slumped deep into a couch. Including myself and Yozuki, there were six people gathered in the lobby. Apparently, there were twelve guests scheduled to stay here tonight, so half of them were gathered in this room.

What kinds of people were the remaining guests? As I sat thinking that, I saw her. Instantly, all of my hairs stood on end. I couldn't believe my eyes. What... What was she doing here?

It looked like she'd just come from the west building. She had long black hair down to her waist and a cool, beautifully shaped face. Her eyes were large and almond-shaped. I've never seen a girl more beautiful than her before. I probably never will.

But she looked a bit more mature than she did in my memories. Well, that was only normal. It had been over a year since the last time I saw her.

Before I'd even realized, I'd stood up and approached her. She noticed me and her eyes went wide. In a surprised voice, she asked 

“Kuzushiro?”

Instead of nodding, I said

“It's been a while, Mitsumura.”

Ah... I'm glad I came. When Yozuki said 'let's go hunt for the yeti', I wasn't sure if she was serious, but either way, this is more than enough of a reward.

“It's been a while, Kuzushiro.”

And she laughed.

After a year of separation, this was the first meeting between myself and Shitsuri Mitsumura.

“Kasumi, who is this girl?”

Yozuki suddenly appeared next to me, apparently curious about the relationship between me and Mitsumura. “There's not much to tell,” I said.

“We were classmates in middle school. We were in the literature club together.”

We were also the only members of the literature club. Because of that, I spent most of my time after school with her, until the day she quit.

When I told that to Yozuki, she made a face.

“I see,” she said. “So this is your ex?”

“No, she's not. What did you hear me say?”

“So you're more than friends but less than lovers?”

“Seriously, where are you getting this?”

“Kuzushiro, who is this?”

This time, it was Mitsumura who asked. Apparently, she was also curious about my relationship with the other woman.

“Hmm, how should I put it?” That was a hard question to answer. “I guess you'd call us childhood friends? She lives next door. Growing up, she was like an older sister to me.”

“I see.” Mitsumura nodded. “So she's more than a childhood friend but less than an older sister.”

She also said something strange.

I gave her a questioning look, then asked her what I really wanted to know.

“By the way Mitsumura, why are you here?”

“Did you come here looking for the yeti?” asked Yozuki.

“Yeti? No, I'm just here on a trip,” said Mitsumura. “Wait, there's a yeti?”

Yozuki puffed out her chest.

“There will be.”

“No, there won't,” I said.

 “So which is it?”

Mitsumura looked confused, then let out a small giggle. When we both tilted our heads, she smiled and said “It's just nostalgic is all. It's been a long time since I was able to talk to Kuzushiro like this.”

“I see, that does sound nostalgic,” Yozuki agreed. Then, intrigued, she asked “What was Kasumi like in middle school?” Mitsumura replied “Well...” and looked as though she were searching her memories.

“I don't know how to describe it, but he was always very intense. He would walk around with this expression on his face that said 'I'm a loner, a rebel'.”

What kind of face is that? I don't think I would have ever walked around like that, even if I was in middle school.

“I also heard rumors like 'Once I see something, I can remember it forever, as though it were a photograph. But I don't use it for tests because it puts too much stress on my brain. I'll only use this power when the world is in crisis.' He used to boast about things like that to his friends.”

No! Stop! It's too cringe! I never said that! Surely the statue of limitations must have expired on that by now?

Yozuki ignored my mental screams of anguish and said:

“Oooh! Tell me more!”

“Alright then, let's get some drinks.”

The two of them, having bonded over their shared love of mocking me, took a seat at a table together. I sat with them. Mitsumura may have looked like a serious cool beauty on the outside, but she was quite the eccentric. I needed to keep an eye on her and make sure she didn't say anything strange.

As I was keeping watch on their conversation, the man came back from the west building. He was the dull one in glasses, the manager of Riria Hasemi, the morning drama actress. What was his name? Manei? Mr. Manei took a seat across from Riria, who was relaxing on a couch. He took a sheet of paper from the work bag in his hand and put it on the table.

Riria, who was still drinking her grapefruit juice, looked at the paper and said

“Manei, what is that?”

“It's a questionnaire form for a variety show.”

“Bleh!”

Riria made no effort to hide her disgust. She took a sip of juice through her straw.

“I don't really feel like it right now. Manei, you do it.”

“No, you have to fill it out properly.”

“But I'm just a delicate little princess who can't lift anything heavier than a pair of chopsticks. A pen is heavier than a pair of chopsticks, right?”

“It depends on the material.”

He had a point.

Riria looked to be getting angrier.

“Don't you get it? I said I'm not writing that thing.”

“But variety show surveys are important,” Mr. Manei said, keeping surprisingly firm. “The amount of opportunities you get as a performer will change depending on how much of the questionnaire you fill out. The more you write, the more MCs will be willing to give you a chance. On the contrary, if your questionnaire is sparsely filled, the staff will think you're unmotivated.”

“Yeah, I know all that. That's why I told you to write it.” 

“We're going in circles.”

“I wonder if there's some sort of magic time loop?”

Riria finished her juice and roughly snatched the questionnaire from Mr. Manei's hands.

“I get it already, I'll fill out your stupid survey. I'm going to my room!”

Riria quickly stood up and sulked off towards the west building. Mr. Manei let out a deep sigh.

While all that was happening, Yozuki and Mitsumura were still having their lively talk about my middle school days. The black history was being unveiled... However, they suddenly stopped. Just as Riria left the lobby, it started to snow.

Outside the window... there was snow.

The glittering lights danced vigorously across the sky and fell in a splendid performance. The garden was already covered in white. Come to think of it, this was the first time I'd seen snow this year. And it was the first time I'd seen snow on a trip, too. Clearly, it was exciting. The other guests in the lobby were also looking out the window.

Yashiro the company president, Ishikawa the doctor, and Sagurioka the detective. Mr. Manei, who'd just had that argument with Riria, was also looking out at the snow as if to distract himself. Miss Meirozaka, who was delivering a coffee, had also stopped to stare out the window. The manager, Ms. Shihai, was the only one focused elsewhere, tapping away at the computer behind her desk.

I'd heard that there were a total of twelve guests staying at the hotel tonight. Seven of them were currently gathered in the lobby. Of the guests whose identities I knew, the only ones not present were Riria and the British girl, Fenrir Alicehazard.

Fenrir also appeared in the lobby about ten minutes after the snow started. It seemed she'd been taking a walk in the garden, because she was wearing a coat with snow on the shoulders. And then there were eight. Fenrir, her silver hair wet with snow, wandered around the lobby for a while, but when she spotted me, she smiled and approached.

“Mr. Kuzushiro,” she said and placed something on the table. It was a rabbit made of snow. “A souvenir.”

The small snow rabbit stood on the wooden table. Cute.

Fenrir smiled.

“I hope it tastes good.”

“Oh, you... want me to eat this?”

“It's full of red bean paste.”

“...Really?”

I was hesitantly preparing to take a bite when she laughed and said “Just kidding.” She left us like a mischievous child and moved to the window, where she began taking photos of the garden with her phone. The snow was starting to pick up.

About 20 minutes later, the snow stopped. Although it had only been brief, it was enough to completely cover the garden in silver. The boxed garden of the mansion grounds, contained in the high walls, was painted pure white.

As soon as the snowfall stopped, the eight guests gathered in the lobby began to leave their seats one by one. Ms. Shihai, who'd been working behind the front desk for a long time now, stretched and went towards the dining building. Miss Meirozaka went behind the counter and took her place.

I decided to head back to my room, too. The snow rabbit Fenrir gave me was starting to look a bit sluggish. I needed to put it back in my room's freezer before it melted.

At 7:00 P.M., Yozuki and I went to the dining building.

It looked like dinner had started without us. The north wall of the dining room was made entirely of glass, letting in the light. Although it was dark now, it probably felt extremely open during the day. There were several tables in the large room, and each guests was sitting and enjoying the food. The seats appeared to have been assigned in advance, and we sat at the table with nameplates for myself and Yozuki – or rather “Mr. Kuzushiro” and “Ms. Asahina”. Miss Meirozaka saw us and immediately brought over our food.

“'The chef's whimsical hors d'oeuvres ~Brought on the winds of Southern Europe, Western Europe, and Northern Europe~'”

We'd suddenly been presented with a mysterious dish. I didn't know what sort of cuisine this was supposed to be.

“It's fusion cuisine, isn't it? This is a Spanish omelette, right? And this carpaccio is from Italy, and this whatever it is is made with herring from Scandinavia.” Yozuki took a bite of the whatever it was made with herring. “What the heck? This is great!”

“Really?”

“Try it. It's so good, your tongue will melt right out of your skull.”

That didn't actually sound appealing.

Like Yozuki, I ate some of the herring dish. And I couldn't help but cry out.

“What the heck? This is great, isn't it!?”

“Your tongue is melting, right?”

“It melts in your mouth. This is the greatest seafood dish I've ever had in my life.”

I was so excited about the food that I immediately went into “call the chef” mode. I snapped my fingers to summon Miss Meirozaka, who was serving someone nearby.

When she came over, I immediately started talking.

“This is delicious!”

“Huh, okay.”

Those were probably her honest thoughts, but they still hurt my feelings.

Yozuki and Miss Meirozaka started talking, completely ignoring me.

“Did the manager make this?”

“Yeah, Shihai made it. It's a bit much, but she's as good as any top chef back in Tokyo.”

“These vegetables are also very fresh. These tomatoes, for instance.”

“Oh, those were sent by Shihai's younger sister. Shihai's twin sister is a farmer out in Yamanashi.”

Their conversation was quite lively. Strange. Even though Miss Meirozaka had completely ignored me...

Then, I remembered to ask something that had been on my mind for a while now.

“Miss Meirozaka, what's your relationship with Ms. Shihai?”

“What do you mean, our relationship?”

“It's just that since the two of you run this hotel together, I thought you might have known each other before.”

Miss Meirozaka both worked and lived in this hotel out in the middle of nowhere. I thought she probably wouldn't have done that for a stranger.

And it appeared my hunch was right.

“Yeah, we knew each other before this,” Miss Meirozaka said. “Shihai was my teacher in high school. We met pretty often after graduating, and one day, I heard she was quitting teaching to run this hotel, so I thought I'd help out. Well, I was a NEET at the time anyway.”

I'd argue she was still a NEET.

“Still, it's amazing,” Yozuki said through a mouthful of herring. “Ms. Shihai's only 30, right? And yet she had the money to buy this huge mansion?”

Yozuki, who'd been so impressed, suddenly looked up as though she'd realized something. Holding up her index finger, she quietly asked something.

 “Could it be that she won the lottery?”

“That's not it,” Miss Meirozaka shook her head. “But you're close.”

“Close?”

“Shihai's always been popular, especially with older folks,” Miss Meirozaka explained. Then she lowered her voice. “Around when I graduated high school, Shihai married a wealthy man over 40 years older than her, and when he passed away only the next year, she inherited billions. She bought this hotel with the money, and now she runs it as she pleases.”

“I see,” Yozuki said. “Ms. Shihai has a past like that.”

“She's a femme fatale,” Miss Meirozaka said. “Even when she was a teacher, she was always getting in trouble for things like dating male students. But strangely enough, she was still a good teacher who was liked by her students.”

Miss Meirozaka left things there and walked away. She never clarified if she was one of those students who liked her.

After dinner, I took a bath in my room, then went out to get a drink from the vending machine in the lobby. As I was walking down the hallway in the west building, I saw a suspicious figure: the morning drama actress Riria Hasemi. She held what looked like a walkie-talkie in her hand and was pointing its antenna this way and that with an intense look on her face.

“Um, what are you doing?”

“FUNYAAA!”

Riria was surprised to hear me sudden call out from behind her and made a strange noise. She took a deep breath, turned to me, and gave me a strange look.

“Who are you?”

“I'm just a guest.”

“And what right does a mere guest have to address the great and wonderful Riria?”

Somehow, she said that with a straight face. Seeing the expression I made in response, Riria slowly began to regret her decision. She suddenly began panicking.

“No, no, that was just a joke! You should totally keep talking to me. I love talking to my fans! I'm even thinking about changing my name to 'Riria Fanservice Hasemi'.”

“Huh?”

“'Huh'? What's 'huh'? That's a pretty lame reaction. Are you nervous? That's understandable. I am famous, after all. My shows have an average audience rating of 25%.”

“Huh?”

 “............HIYA!”

“GYAAAAAAA-!”

For some reason, she kicked me right in the shin. What was with this girl? Should I go to the weeklies with this?

Without even apologizing, Riria looked down on me as I writhed on the floor in agony.

“If you breathe a word about this to the weeklies, I'll kill you.”

She said that with a smile on her face... What was with this girl? There were limits to how bad a person's temper could be.

“So...” When I finally recovered from the pain, Riria condescended to ask me, “Why did you talk to me? You want an autograph? Maybe a photo? If you want hush money for kicking you in the shin, I'd be happy to do that much.”

“That's not it,” I groaned. I definitely didn't need this girl's autograph anymore. “I was just curious what you were doing with that strange machine.”

I pointed to the walkie-talkie-like device in her hand. Riria seemed a bit annoyed that I didn't want her autograph, then looked bored and said “What? You mean this?”

She held the device up to me.

 “It's a bug sweeper.”

“A... bug sweeper.”

Why did she have something like that?

Riria seemed to understand I had my doubts and took a deep breath.

“You see, I'm a nationally famous actress.”

“Huh?”

“Do you want to get kicked again?”

“I'd really rather you didn't.”

“Really? Actually, are you sure you aren't acting like that on purpose because you want me to kick you?”

That was a ridiculous question. ...What? No, really, it was, I swear!

“Well, anyway,” Riria said, “I'm a nationally famous actress whose debut song has 200 million plays, so I'm always being hounded my the media and even stalker fans. That's why I must always remain vigilant! Whenever I travel for work and stay at a hotel, I always use this machine to check for listening devices or hidden cameras in my room.”

She waved the machine that looked like a walkie-talkie.

I was about to say “Huh?”, but then I hurriedly changed to an “I see!” I was being subjected to so much stress today. “That machine picks up the radio waves emitted by listening devices and hidden cameras!”

“See, you get it, servant boy.”

“...I'm not a servant.”

“Did you say something, servant boy? As long as I have this, I can easily find any bugs planted in my room. I spent about 30 minutes doing a thorough investigation today.”

“Oh, I see.” That this girl has way too much free time. If she had that sort of time, she could have at least filled out that variety show questionnaire.

But then, I realized something.

“If it's something like that, you should just have your manager do it. There's no need for you to go to the trouble.”

When I said that, Riria looked at me with pitying eyes, like I was a child.

She sighed.

“What are you talking about? There's no way I'd ever make Manei do it.”

I see, I think. I looked back at Riria.

“Mr. Manei certainly does seem busy. You're trying to lighten the burden on him, right?”

Riria recoiled in shock.

“What? No, I just don't want him in my room! I mean, he's a total idol otaku, you know? He even goes to handshake events on his day off. Isn't that gross? I'd never let a guy like that in my room. Who knows what he'd do? I bet he'd be the one to plant a bug in the first place.”

Riria's trust in Mr. Manei was zero. I regretted talking to her more and more.

Riria seemed to get tired of talking to me, so she went back to searching for bugs with the walkie-talkie-esque bug sweeper. I told her “See you later.” I expected her to ignore me, but Riria did reply “Good night, servant boy.”

I put the coins into the vending machine and got myself a fruit milk. As I drank it, I idly flipped through the channels on the TV in the lobby and saw a news story about a bus crash that happened nearby. Apparently, two people had died. The news anchor was reading out their names. “The deceased are Chizuru Nakanishi and Haruki Kuroyama...” A voice shouting “What!?” came from behind me. When I turned around, I saw Miss Meirozaka.

She looked unusually surprised by the news. I frowned and asked what was up.

“Did you know them?”

“We'd met.” She stammered a bit. And then, in a confused voice, she said “They were both guests planning to stay here tonight. I thought they were a bit late, but I never expected something like this...”

My eyes went wide. The guests who were supposed to be staying here died?

Hearing our conversation, the other guests in the lobby gathered around. “Is that true?” asked Detective Sagurioka. “I can't believe it,” said the British girl, Fenrir. “Things like this do happen,” said someone in a leisurely tone. If I remembered correctly, that was Dr. Ishikawa.

“What, what, what's going on?” Yozuki, who'd just entered the lobby, joined us. When she heard what was happening, her eyes widened, as expected.

At that moment, I heard the sound of footsteps coming from the entrance.

In that tense atmosphere, everyone turned at once. We'd already been confused by the accident, and the man who appeared before us upset us even further.

Before everyone's eyes...

The man was about 30. Judging by the way he'd come in through the front door, he was probably a guest. There should have been a total of twelve guests staying in the hotel tonight. There were nine people already accounted for, and two of them had died in an accident. In that case, this man who'd just arrived was the twelfth guest. The late arriving final guest.

The problem was his appearance.

The man was dressed in religious garments like a Catholic priest. He was dressed in all white, with a crucifix drawn on the left chest. However, the figure being crucified on the cross wasn't Christ, but a fleshless skeleton.

I'd seen that morbid image before. It was the logo of a certain religious organization. I gently whispered the name of the sect.

“Tower of Dawn.”

My words sent another ripple of tension through our group. “Hey, he's from Tower of Dawn,” Yozuki said. “They worship corpses...”

Technically, that wasn't correct. What Tower of Dawn worshiped wasn't corpses, but crime scenes.

Tower of Dawn was a religious group that had been gaining new followers at a rapid rate lately, but it wasn't one of those new religious groups. Its history went back surprisingly far. It was founded in France in the 17^th century. Well, I didn't know if that was actually true. But whatever the case, it seemed they had close to 100,000 followers around the world. It was introduced to Japan after the war, but only began to expand its influence three years ago – after the first Japanese locked room murder.

Tower of Dawn made the scenes of murders into objects of worship. Photos of crime scenes were their sacred objects. A murder scene was filled with the victim's negative energy. It was their doctrine to purify them through prayer, thus turning the negative energy to positive and achieving happiness.

And among the murder scenes they revered, the one they held in highest regard was the scene of a locked room murder. Well, that doctrine was something they made up after the start of the locked room boom. Since it was closed off, the victim's grudges would be trapped and accumulate, so more happiness energy would be produced when it was purified, or something.

Tower of Dawn expanded its influence in Japan by exploiting the locked room boom that started three years ago. On the other hand, they were also the subject of unpleasant rumors. Some even said they committed murders themselves to increase the number of crime scenes to worship.

We eavesdropped on the talk between Miss Meirozaka and the man in the priest's garments. The man's name was Kanzaki, and it seemed he was a priest of Tower of Dawn. I heard Yozuki murmur “He's a priest, and his name incorporates the 'kami' kanji.”

Miss Meirozaka asked something as she went through the check-in procedures at the front desk.

“Mr. Kanzaki, why did you chose our hotel? Is it to see the scene of that locked room? The scene of the 'House of Snow Locked Room Case' organized by Byakuya Yukishiro?”

“No, I'm not here for that.” Kanzaki shook his head calmly. “No one died there. It isn't an object of our faith.”

“I see, then why are you here?”

“We received a tip,”

Kanzaki was still as calm as could be.

“That a locked room murder will occur in this mansion tonight.”

When I woke up, the clock showed 8:00 A.M. When I opened the curtains, the white garden was reflected back at me. It had snowed yesterday afternoon. The amount of snow on the ground hadn't changed since yesterday, so it hadn't rained or snowed during the night.

After washing my face, I changed clothes and went to wake Yozuki in the next room. When I knocked on the door, a sleepy girl appeared before me, speaking grumpily.

“What do you want? It's so early...”

“I just thought we could have breakfast together.”

“Are you crazy, Kasumi?”

She gave an unexpected reply. Yozuki spoke with a sigh.

“There's no way I can eat breakfast this early in the morning. Everyone knows that on your days off, you don't eat breakfast until after noon.”

Wouldn't that already be lunch?

“Stop making sense, dummy.”

She slammed the door in my face. I was very sad.

When I reluctantly went to the dining building by myself, I found several people already there. Breakfast seemed to be as simple buffet with primarily western food, and there were about ten items to chose from. I got some omelette and sausages, assembling a British-style breakfast plate.

As I was looking around wondering where I should sit, I saw her eating alone. I put the the tray before the seat across from her.

“Good morning,” I said.

“Yes, good morning,” Mitsumura replied.

On Mitsumura's plate were two omelettes and two fried eggs. It was all eggs. Come to think of it, she had always liked eggs that much. When we went to that Chinese restaurant together, she ate fried egg with kikurage mushrooms and crab rice fried in egg.

As I was immersed in those memories, Mitsumura gave me a suspicious look.

“What are you smiling at?”

“I was just thinking, you still like egg, don't you?”

“I was a chicken in my past life.”

“Is that so?”

“Yes, and I got older and couldn't lay eggs, so I was fried.”

“How tragic.”

“That's why I'm storing up nutrients so I can give birth to more children in my next life.”

“Are you planning to be a chicken in your next life, too?”

“Unfortunately, I am cursed to alternate between being a human and a chicken.”

Mitsumura joked like that with a straight face. It felt nostalgic somehow. Come to think of it, did we used to talk about nonsense like this back in middle school?

Around 10:00 A.M., Mitsumura and I were playing Othello on our phones in the lobby when Yozuki arrived, looking a bit impatient.

“Is breakfast over yet?”

She looked like she'd just woken up. I turned over an Othello piece and said “Yeah. Breakfast was from 8:00 to 9:00.”

“Are you serious?” she replied with a straight face. It wasn't that serious, but that was what I'd been told when I asked at the front desk yesterday.

Yozuki clutched her stomach and gave a look of despair.

“But I'm hu~ungry~.”

At that moment, Mitsumura flipped my Othello pieces. “Ah,” I said. “It's pure white,” said Yozuki. Indeed, the board was solid white, and my black stones were completely annihilated. ...Is it even possible for an Othello game to end like that?

“Hey, forget about that, I need breakfast.”

“Be patient,” I told Yozuki grumpily. “Lunch is at noon.”

“Don't take your anger over your humiliating defeat out on me.”

“It wasn't an embarrassing loss! It was really close.”

“Close as opposite sides of the same sheet of paper,” said Mitsumura, looking quizzically at the board.

Ms. Shihai, still at the front desk, couldn't stand to listen any longer and came over. “Um, can I get you something?” she asked kindly. “Though it will just be leftovers.”

“Oh, really? Yeah, made it!” Yozuki cheered without a hint of shame. This girl had no interest in being an adult.

Then, Ms. Shihai appeared to remember something.

“Come to think of it, besides Ms. Asahina, there was one other guest who never showed up for breakfast.”

Someone other than Yozuki?

“Did they oversleep?” I asked.

“Maybe, but... it's strange.”

“Strange?”

“For some reason, there is a playing card attached to the door of their room.”

That made me raise my eyebrows. That certainly was strange...

“Is it a prank?” Yozuki asked, interested. “Or did the person staying in the room put it on themself?”

“But why would they have done that?” Either option left that question unanswered.

After thinking about it for a while, I realized I'd forgotten to ask Miss Meirozaka something important earlier. So I asked now.

“Who is the guest staying in the room with the playing card pasted on it?”

“It's Mr. Kanzaki.”

“Kanzaki?” Which one was he?

“He arrived just last night.”

Ah, that was right. The priest from Tower of Dawn.

Mitsumura, who was closing the Othello game, tilted her head and said “A guest arrived last night?” Come to think of it, Mitsumura hadn't been there when Kanzaki arrived.

“Well, for the time being, we should check on him,” Yozuki suggested. “Then say you should go to the scene 100 times, so if we go there now, we might find something. That's my great detective's intuition speaking.”

“Yozuki is a great detective?” Mitsumura chimed in.

“You're awfully motivated.” I looked at Yozuki with confusion. I thought Yozuki wasn't interested in these sorts of mysteries. She hadn't shown any interest in the House of Snow Locked Room Incident left behind by Byakuya Yukishiro.

Yozuki shyly scratched her cheek. “Actually, I read one of those 'everyday life mystery' novels for the first time recently.” It was a shocking confession.

“So I wanted an excuse to say something like 'How curious...'”

 

Kanzaki's room was on the third floor of the east building. The four of us, Yozuki, Ms. Shihai, Mitsumura, and myself, walked down a hallway covered in the same sort of long pile carpet as the second floor.

Kanzaki's room was directly above the room where the “House of Snow Locked Room Case” had taken place. And on the door of the room, there was a playing card taped to the door, just as Ms. Shihai said. The numbered side was up. The card was the ace of hearts.

“That is strange,” I said, removing the card from the door. On the back was a strange picture of a rabbit and a fox having a tea party. It appeared to have been hand-painted, not printed. It was painted in watercolor like an expensive postcard, and there even appeared to be an artist's signature in the right corner.

“That must be one expensive deck of cards,” said Yozuki.

“It certainly would be strange for a prank,” Mitsumura said as she looked at the card.

At that moment, we heard a man scream from the other side of the door. The sound was deafening, making everyone present shiver. I quickly grabbed the doorknob. I turned it and pushed the inward opening door, but it didn't budge. It was locked.

“Where's the room key?” I asked. “Mr. Kanzaki still has it,” Ms. Shihai replied. That was right... I realized a moment too late. This was Kanzaki's room. Kanzaki must have still had the key.

“What about the master key?”

Ms. Shihai shook her head.

“There is no master key for the east building. There is for the west building, but the key systems are different between the east and west buildings. I can't unlock this room with the west building's master key.”

I was starting to get the strangest sense of deja vu.

“Okay, so where's the spare key?” Yozuki asked impatiently. “Isn't there a spare?”

“There isn't any spare,” Ms. Shihai shook her head again. “All of the keys in the House of Snow are extremely special, there's no way to copy them.”

“Does that mean we have to break a window to get into the room?” Mitsumura asked, but Ms. Shihai gave a bitter face and said “No, we can't do that either.”

“There are bars on the window, so people can't get in and out through there.”

“Then, how on Earth can we get inside...?”

Silence fell over us... The only option left is...

“What happened!?”

At that moment, Sagurioka came running. Miss Meirozaka and the remaining guests were also there. That meant everyone in the hotel with the exception of Kanzaki was gathered here.

I explained the situation. About the playing card found on the door, the screams we'd heard from the inside, how there was no way to open the door and no way to go in or out through the window.

Which meant the only option left was...

“Then we have to choice but to break down the door,” Sagurioka said. Then he turned to Ms. Shihai. “Is that alright?”

Ms. Shihai nodded her head.

“We have no choice. Please.”

Sagurioka and I took position in front of the door. Then, with the knob still twisted, we threw ourselves against it. The door creaked. We repeated that ten times total, then the door finally opened. Sagurioka and I tumbled forward into the room.

It was pitch black. Eventually, the ceiling lights came on. It seemed Miss Meirozaka turned them on for us.

Kanzaki wasn't in the room.

“Maybe he's in that room over there?” said Riria's manager, Mr. Manei. Apparently, the room Kanzaki was staying in was originally two guest rooms. In other words, there was a door to the next room. The door, on the left, was open. The door was right of center on the wall, or in the back of the room when viewed from the entrance.

We all fearfully approached the door. I was the first to see into the next room. The lights in the adjacent room seemed to be linked to the lights in the main room, so by turning in the lights in the main room, we'd also turned on the lights in the adjoining room.

So I could see it clearly.

The figure of a man. Kanzaki's corpse was still dressed in his religious garments.

Someone's scream echoed within the room. It was Riria's voice. The scream was completely different from her bratty behavior last night...

However, the scream didn't reach my brain. I saw it a split-second before her scream, and it stunned me so much that the outside world faded away.

“Are you kidding me?” I muttered, picking it up from where it had fallen a bit away from the corpse. Sagurioka saw me and approached in a panic. And he said the same thing as me.

“Are you kidding me?”

This must have been some kind of joke. Because the object I held in my hand was...

A small plastic bottle the size of a film canister with a tightly closed lid.

And inside that small bottle was a key. I couldn't have been sure, but it was probably the key to this room.

“A copycat crime?” asked Sagurioka. I nodded.

It was definitely a copycat crime. However, I didn't know the trick – it was based on an unsolved case.

Glaring at the key in the bottle, I said:

“This incident is a reenactment of the House of Snow Locked Room Case.”

There was a knife in Kanzaki's chest. There were no marks on his neck, so it was safe to assume that was the cause of death. The knife was thrust straight vertically into the chest of the corpse lying on its back. Its blade was about 30 centimeters long, and the blade, facing the door connecting the main and adjacent rooms, shone in the light. The length and shape of the blade suggested it wasn't a kitchen knife, so we could assume the murderer had brought it from outside.

The corpse lay just in front of the door between the main and adjacent rooms, just like in the House of Snow Locked Room Case, and beyond the corpse was a window covered in thick blackout curtains like you'd find in a darkroom. There was a gap of about a centimeter between the bottom of the curtains and the floor, but there was still almost no sunlight passing through. In that case, there was no way the light would ever reach the main room. Even though it was almost noon, it was understandable that the room was black as midnight.

When I opened the curtains, there was a window with a lattice. It was exactly the same as the one at the scene of the House of Snow Locked Room Case. The sliding window was currently open, but the lattice ensured that nobody could go in or out through it. And the gaps in the square grid looked too small to fit the room key through.

And, just like in the House of Snow Locked Room Case, a voice recorder had been placed next to the corpse. When played, a man's scream could be heard. When I'd first heard it, I thought it was Kanzaki's voice, but apparently it was someone else. It was probably audio from a movie or something.

Next, I looked at the small plastic bottle in my hand. This lid, too, had an O-shaped protrusion. I opened the bottle and took out the key. I needed to confirm that this was the real key, so I went back to the door and inserted it into the keyhole. When I turned the key, it moved. This was the real key after all.

“Anyway, we need to call the police,” said Mr. Manei, as if he'd just remembered. Beside him, Riria's body was twitching as she cried. “Ah, right, the police,” said Ms. Shihai, as though she'd also just remembered.

We all went to the lobby. As we watched Ms. Shihai dial the police, her eyes widened. She hung up the phone and spoke to us, upset.

“I can't get a dial tone. Maybe the phone line is down.”

“Or maybe it was cut,” said Sagurioka, putting a hand on his chin. When everyone's eyes turned to him, the detective just shrugged. “It's possible, isn't it? It's a staple of closed circle mysteries.”

“Closed circle?” asked Yozuki.

“Oh, you don't know? That's rare,” said Sagurioka. “It's a type of mystery where murders occur in isolated mansions or islands cut off from the outside world. In such cases, the phone lines are usually cut so the police can't be called.”

Yozuki looked confused.

“Would it be inconvenient for the culprit if the police come?”

“Of course. If the police intervened, then the culprit wouldn't be able to act freely. They wouldn't be able to kill their next target.”

“That's...” Riria's face went pale. “Are you saying the culprit isn't done? They're going to kill someone other than that priest?”

“Most likely. Otherwise, there would have been no reason to cut the phone lines.”

Riria was white as a sheet. She frantically pulled out her phone and tapped the screen with trembling fingers. “The police... I have to call the police!” she cried. But then, she mumbled “Out of range...” as though she'd been drained of all energy.

“We're trapped!”

Riria threw her smartphone on the lobby floor. “Please, calm down, Miss Riria!” Mr. Manei hurriedly went to calm her down. Then, he turned an annoyed look towards Sagurioka.

“And you! Please stop saying things that accomplish nothing but frightening those around you. There is no reason to believe that a serial killer lurking among us!”

Sagurioka shrugged, a bit annoyed.

“Well, sorry. That was rude of me,” he said, but he continued firmly. “But unfortunately, it's almost certain that this will become a serial killing case.”

“And what is your basis for that?” asked Mr. Manei.

“The playing card attached to the door,” Sagurioka said, turning his gaze to me. “Young man, you said earlier that there was a playing card taped to this door, right? Could you show it to me?”

“Ah, sure,” I said, pulling out the card I'd put in my pocket. The ace of hearts. On the back was a watercolor painting of a rabbit and a fox having a tea party.

After taking the playing card, Sagurioka looked at the front, then the back. Then he said “So I was right. When I heard there was a playing card stuck to the door of the crime scene, it hit me. Seeing it now, I'm convinced. This is the same type of card used in the Playing Card Serial Murder Case.”

Some people tilted their heads in confusion, while others went pale. I was in the latter group. The Playing Card Serial Murder Case was an unsolved serial murder that occurred about five years ago. There were three victims, and all three of them had a playing card left at the scene. I searched the corners of my memory. Just as I was about to recall the details of the incident, a steady voice spoke up.

“Five years ago, on the 21^st of April, a man was bludgeoned to death in an alley in Kanagawa Prefecture.”

Everyone's eyes turned to the speaker. A beautiful girl with silver hair – Fenrir Alicehazard smiled back at them. “I just so happened to remember it,” she explained, then began in a calm voice.

“The male victim was known as a great detective, not only highly skilled, but blessed with incredible luck. In the past, he'd coincidentally run into the culprit of an unsolved case in a bar, and the other man drunkenly boasted 'I got away with murder'. That incident led to him gaining fame among law enforcement. However, his fame was shattered six months before he was killed when he caused a traffic accident. He killed someone driving while distracted, forcing him to retire from the police force. Naturally, he must have been resented by the bereaved family of the person he'd killed, so the police investigated along those lines. But in the end, the culprit was never caught. And there was something about the case that was incredibly odd.”

Fenrir cut herself off and pointed at the playing card in Sagurioka's hand.

“A playing card just like that was found lying next to the corpse. The card was the six of hearts.”

Everyone looked at Fenrir in astonishment as she spoke smoothly. She smiled and said “I just so happened to remember it.” Could it really have been so convenient?

Taking a deep breath, Fenrir explained the next incident.

“The second incident occurred five years ago on the 6^th of July. The body of a Chinese man in his 30s was found strangled to death in the parking lot of an apartment building in Chiba Prefecture. The man was a researcher working at a university. He was said to have been extremely talented from a young age, but conversely, he looked down on his father, who had no academic background, and hadn't returned to China in over a decade. It appears he was attacked and killed by someone as he was returning home from the university. The murder weapon was a length of plastic packing string, and a playing card, the five of hearts, was found lying next to the man's corpse.”

She went straight to explaining the last incident. “Four months later,” she said.

“The third – and final – incident occurred on the 12^th of November five years ago. A man who ran his own company was poisoned in an apartment in Tokyo. A new type of poisonous mushroom, similar to the matsutake, was found in his stomach, and it was believed poisoning from that mushroom was the cause of death. The company the man ran was a so-called 'black company' that forced its employees to work unreasonable hours, and it was speculated that he was resented by many people. But once again, the case went unsolved. And a four of hearts was left next to his corpse.”

When Fenrir finished her story, everyone's faces clouded over. Did that mean the culprit who'd killed three people five years ago had restarted their crime scene here in this mansion?

“Well, there you have it,” said Sagurioka. Then he praised Fenrir with a shrug. “That was pretty impressive. Even though it was a hot topic at the time, you remembered the fine details well. Well, so do I, of course.” It was hard to tell if Sagurioka was telling the truth or just showing off.

“But, that doesn't mean this case has the same culprit as that Card Whatever Murders Case,” Riria said. “It could just be a copycat... No, it's gotta be. After all, it's easy to imitate something like this if you just buy the same kind of cards!”

“That's certainly possible, too,” said Sagurioka.

“No, that isn't possible,” said Fenrir, shaking her head. “The playing cards left at the crime scenes were one of a kind, and no two were alike. There is only one set of them in the entire world. There's no way another person could have obtained the same sorts of playing cards and become a copycat criminal.”

Hearing her explanation, Sagurioka shrugged.

“She's right.”

“But, isn't it possible these cards were just forgeries? The culprit could have just prepared fake playing cards and used them.”

“That could have happened,” said Sagurioka.

I wondered what this man called Sagurioka actually thought.

“Then why don't we just check?” Fenrir took out her smartphone and opened an app. Everyone looked at her screen, puzzled.

“What's that app?” asked Yozuki.

“It's an art authentication app,” Fenrir said. “If you take a photo of the artwork you want to appraise with this app, it will determine whether it is genuine or not. This app contains data on photos of authentic art. The system uses AI to check the data. No matter how skilled the forger is, it's impossible that they can make an item completely identical to the original piece, so it's easy to determine authenticity,” she said as she used her smartphone. “And this app also contains data on the cards used in the Playing Card Serial Murder Case. All 53 cards, including the joker. Each card has a picture of a tea party drawn on. The pictures are watercolors, and each is slightly different, so the data for all 53 cards is necessary to authenticate them. Incidentally, the pictures were taken by an art dealer long before the incident occurred, in other words, long before the criminal got their hands on the cards. The police used this same app to authenticate the cards at the crime scenes. The story of how they determined the authenticity of the cards is quite famous.”

“It is famous,” said Sagurioka.

“Well then, Mr. Sagurioka.”

“What? Are you doubting me? I did know that already.”

“No, that isn't it. I would like to check the authenticity of the playing card, so may I see it?”

Fenrir looked at the playing card in Sagurioka's hand. The ace of hearts was the card attached to the door during the incident. Sagurioka started, then handed it to Fenrir, saying “Ah, here you go.” She took a picture of it with her smartphone. Immediately, we heard a tinkling sound.

“There are the results. It looks like this is the real thing.”

The atmosphere was suddenly suffocating.

The culprit of a five year old serial murder case has resumed their killing spree here in this mansion.

“Including the ones from five years ago, this brings the total number of victims to four,” Fenrir said. “There are a total of four playing cards that have been used so far. Their numbers are 6, 5, 4, and ace. It isn't a countdown, and I can't make out any rule, but there is one thing they all have in common: they're all from the suit of hearts. If we assume the culprit only uses heart playing cards, then there are only so many cards left to them. There are nine cards, ten if we include the joker. And this is the important part: The total number of people in this building, guests and employees, is...”

“Eleven,” I whispered. A chill ran down my spine. There were eleven people here, and the culprit had ten cards left. That meant....

“Does that mean the culprit is planning to kill everyone but themself?”

Sagurioka's question made everyone's faces harden. Nearly ten seconds passed in total silence.

“Don't be ridiculous!”

A silence which was suddenly torn to shreds. All eyes turned towards the voice. The man who'd screamed was the company president.

Yashiro slowly approached Sagurioka with a face twisted in rage. Then he roughly grabbed him by the shirt. “Gwuh!” He ignored Sagurioka's groan and slammed him firmly into the wall. Then he roared at him with a voice fit to break the window.

“You just keep saying shit without any meaning! Are you making fun of me!?”

“N-No, I'm not!” Sagurioka said in a panic. “It's just logical reasoning based on the evidence.”

“You call that logic? That kinda talk is what we call 'making fun of someone'! Stupid detective! I know a lot more than you! I graduated from Keio University!”

“I graduated Tokyo U.”

“...Fuck you!”

Yashiro punched Sagurioka. It was pretty messed up. Ms. Shihai rushed to stop them.

“Mr. Yashiro, please calm down!”

“You too, Manager!”

“Eh, me?”

“That's right! What the hell are you doing, running a hotel in a place with no cell phone reception!? Didn't you plan for something like this to happen!? A murderer snuck into this place and cut the phone lines!”

“Th-There's no way I could have predicted something like this!”

“Don't make excuses!”

He was still yelling loudly. While everyone else was cowering from his raging, an even angrier voice cut in. It was Riria, her eyes still red and swollen.

“Stop it! Stop arguing over stuff that doesn't matter! It's all a waste of time!”

Hearing that, the president decided to make Riria his next target.

“A waste of time? Are you making fun of me!?”

“You're being ridiculous, old man! I'll freakin' kill you!”

“...I'm going to kill you.”

“Whatever, shut up, old timer. You're so annoying!”

Riria hunched her shoulders like she was ready to fight. Then she exhaled once and seemed to cool down.

“...Anyway, I don't want to spend any more time here. My life's too precious to spend it in a place like this with a murderer!”

So saying, she hurried towards the front door. Mr. Manei stopped her.

“M-Miss Riria, where are you going!?”

“I've made up my mind! We're going down the mountain!”

“Going down the mountain?”

“This might be a land island, but it isn't a real island! We only have to walk for an hour to get back on the road! We'll just hitchhike the rest of the way.”

Indeed, Riria was right. With the phone lines cut and evidence that a serial killer was lurking, that seemed to be the most practical option.

That's why I agreed with Riria.

“Ms. Shihai, I agree with her. Let's all go down the mountain together.”

Riria smiled happily at my words.

“Let's go, servant boy.”

“I'm not a servant.”

We all gathered at the entrance with the bare minimum of luggage. We all left the hotel and headed down the mountain. After passing through the gate in the wall surrounding the mansion and walking for about five minutes, we arrived at the deep valley that cut through the mountain. But I immediately felt a discomfort. Something was missing. What was missing? Ah... That was it.

The bridge.

“The bridge... It's gone.”

Riria groaned. To be precise, the bridge was still there. It just looked different.

The bridge had been burned. It appeared to have gone out a while ago, and we no longer felt any heat. It had probably been started last night.

“A closed circle.”

Yozuki murmured.

That was how the House of Snow was isolated from the outside world.

We all returned to the lobby of the House of Snow, dejected. We we stranded.

“How much food is left in the building?” I asked.

“I believe there's enough to last everyone here half a month,” Ms. Shihai replied.

That meant we could live there for half a month. I'd like to believe that's long enough for someone to notice we were missing and mount a rescue operation.

Then I realized something.

“Are there any guests who were scheduled to arrive after today? If they arrive at the hotel and find the bridge burned down, I'm sure they'll call the police.”

Riria brightened up.

“You're right! Good thinking, servant boy.”

Riria looked expectantly at Ms. Shihai. “We do have guests planning to arrive after today,” she said. The light returned to everyone's eyes. But Ms. Shihai herself had a pained look on her face.

“But I'm afraid those guests won't be coming.”

“W-Why not?” asked Riria.

“It's because... how should I put it?”

“It's 'cause they were a weird guest,” Miss Meirozaka said, taking over. She matter-of-factly explained “Actually, that guest rented out the entire hotel for a week starting yesterday. And they made their reservation six months in advance.”

“Isn't that weird, though?” asked Yozuki. “I made my reservation here a month ago, but I was able to get in normally. If the rooms were all reserved by a prior reservation, it shouldn't have been possible for me to get one.”

“That's what was so strange about them,” Miss Meirozaka said. “They told us that if any other guests made reservations during the period they reserved, we could give them priority over their reservation and let them stay. But they didn't want any guests leaving in the middle of their rental period, or any new guests arriving. They asked us to refuse any reservations for such guests.”

I raised my eyebrows at her explanation. In other words, during the seven-day period they'd reserved, the hotel could make reservations for guests who'd stay for the entirety of those seven days, but any other guests would be refused. The hotel already had a policy of only accepting guests staying for a week or longer, so Yozuki and I were planning to stay here the whole seven days. I guessed the other guests were in the same boat. Therefore, we were all able to make reservations, even though the hotel was supposed to be booked full. However, any guests who'd been planning to start their stays tomorrow or later would be refused.

“That means...” I said.

“Yes, with the exception of the guest who rented out the hotel, no one will be coming here for the next week. That guest was originally scheduled to arrive yesterday, but yesterday morning, they suddenly told us they'd be delayed by a day. But like Shihai said, they probably aren't coming here today, either, right?”

Because they were the killer who'd cut the phone lines and burned the bridge.

They'd rented out the entire building to ensure nobody came to help us.

“That's absurd! How could you have made such a reservation!?” Yashiro was getting angry again. Miss Meirozaka replied calmly.

“They paid in advance, and their money was green as anyone else's. We thought they were a legit guest.”

“What about this is 'legit'!? That's the most obviously suspicious thing I've ever heard!”

“It's easy to say that now, but at the time, we never could have imagined something like this would happen.”

“Sure you could have! Use your imagination!”

“There are limits to the human imagination.”

“Are you making fun of me!? I graduated from Keio University!”

“I was a student at Tokyo U. before I dropped out.”

“...Seriously? You too?”

Yashiro slumped over in defeat. Then, he suddenly stood up from his seat in the lobby and headed towards the west building. I thought he was going back to his room, but soon, he returned with his bags. Ms. Shihai spoke in a panic.

“Mr. Yashiro, where are you going?”

“I'm going home. I don't want to stay here any longer.”

“But if you leave now, the bridge will fall down.”

“I know that! But we can cross that valley by going through the forest, right? That means we can still go down the mountain.”

“Wait! It's too dangerous! It's too steep, there's no way you can make it on foot!”

“It's still safer than staying in here with that murderer! I said I'm leaving! Let go of me!”

“Please, wait!”

As I stared at the two of them in amazement, Sagurioka approached me, laughed, and said “It's gonna be a hell of a night, huh?” He rubbed the cheek Yashiro had punched earlier. “Guys like that always get killed early on.”

Sounded like he was still angry. I wondered if he planned to do the killing himself.

“But that's not what I wanted to talk to you about. Shall we get going?” said Sagurioka.

“Get going?” I tilted by head. “Are you planning on going down the mountain too, Mr. Sagurioka?”

“What? No, don't compare me to that idiot.” Sagurioka looked at Yashiro. He clearly was making fun of him. Then he shrugged and said “The phone lines have been cut, we can't call the police, and we're trapped.”

“It's a complete closed circle.”

“So there's only one thing left to do.”

“What's that?”

“You already know, don't you?” Sagurioka laughed. “We investigate and solve the case.”

That's how the Sagurioka Detective League was organized. The members were Detective Sagurioka, myself, his assistant(?), and...

“Hey you should come, too,” Sagurioka called out to the man watching the fight between Yashiro and Ms. Shihai with a calm look on his face. Dr. Ishikawa, the man in his early 30s... How could he look at such an intense fight so calmly?

That placid expression didn't waver as he asked “Me?” He tilted his head. Sagurioka nodded.

“You're a doctor, right? You should be able to perform an autopsy.”

“I'm sure I could, but it's outside my area of expertise, you know? I'm a heart surgeon.”

“Autopsies are easier than heart surgery.”

“That's true, but... a medical examiner would be upset to hear you say so.”

Dr. Ishikawa laughed. I don't know what he found so funny.

The Sagurioka Detective League gained Dr. Ishikawa as a member...

“May I join your Sagurioka Detective League as well?”

Fenrir Alicehazard was looking at us with pleading eyes. Sagurioka made no effort to hide his displeasure. Apparently, Detective Sagurioka didn't trust her. He may have been wary of the amount of knowledge on the Playing Card Serial Murder Case she'd displayed. No leader wanted to have subordinates who knew more than them.

But in the end,

“Alright, you can come.” Our leader acknowledged Fenrir's membership. She was deeply grateful. Thus, our Detective League had four members.

We returned as a group to Kanzaki's room on the third floor of the east building. Dr. Ishikawa examined the corpse dressed in religious garments, knife still in its chest.

Looking over the scene, I felt a strange sense of detachment. Never in my wildest dreams did I imagine I'd ever be witnessing an autopsy or investigating a real crime scene. This never would have happened in any circumstances other than the one I was in now, the bridge burned down and all communications with the outside world cut off, leaving me the only one able to serve as assistant to a locked room detective.

Eventually, Dr. Ishikawa finished his autopsy and told us his findings.

“The estimated time of death is between 2:00 and 4:00 A.M. today.”

“Late at night... Well, that's what I expected.”

Sagurioka thought out loud. I thought, too. If it was that late, it was unlikely we'd find many people with alibis. It seemed like we wouldn't be able to find the culprit just by narrowing down alibis.

As we thought about that, Fenrir approached the body and crouched down next to it. Then she casually started touching the corpse. “...What are you doing?” asked Sagurioka. Fenrir smiled up at us.

“I was just thinking about performing an autopsy of my own.”

Sagurioka looked at her with a frown.

“Can you even do an autopsy?”

“I most certainly can.”

“Wait, seriously?”

“Despite my looks, I have performed nearly 200 autopsies in my life. I doubt you'll find a more experienced seventeen year old female medical examiner in the world.”

Fenrir said that, then immediately began examining the corpse.

“I'm pretty sure my estimated time of death was accurate.”

Fenrir turned back to him.

“I hear that in the medical world, there is a concept called a second opinion.”

“Yes, though it hasn't widely caught on in Japan yet.”

“I think second opinions should be introduced to the world of autopsies.”

“You mean you think there's a possibility that I made a mistake?”

“No, I think there's a possibility that you're the culprit.”

Fenrir spoke with an innocent smile.

“If a doctor commits a murder in a closed circle situation, they can provide an incorrect estimated time of death, giving themself a false alibi or destroying the real alibi of someone else. To avoid such situations, I believe autopsies should always be performed by at least two people, especially in a closed circle environment.”

“I see, you have a point,” Dr. Ishikawa said with a shrug. Then he gave a gentle smile and said “Please investigate thoroughly. That will prove my innocence.”

“It won't prove your innocence. Even if the result of your autopsy is correct, you could still be the culprit.”

“Well, that's certainly true.”

Ishikawa gave a cheerful, impressed laugh and said “It's hard to escape suspicion, isn't it?” ...What was with this guy? It was strange how unaffected he was by all this.

As Ishikawa had asked, Fenrir thoroughly examined the corpse. Soon, she announced her result.

“The estimated time of death is between 2:00 and 4:00 A.M.”

She gave the same result as Dr. Ishikawa. That at least eliminated the possibility that he was lying about his results.

Fenrir elaborated.

“Judging from the progression of rigor mortis and livor mortis, that estimated time of death is correct. I'd like to check the body's rectal temperature as well, but unfortunately, we don't have the necessary tools.”

“Just who the hell are you?” Sagurioka looked at her suspiciously. Fenrir gave a small laugh and said “Whatever do you mean?” “I think that's obvious.”

Sagurioka got more aggressive.

“No matter how you look at it, it's strange. You're a minor, but you can perform autopsies, and you're strangely well informed about the Playing Card Serial Murder Case.”

The question made Fenrir laugh.

“I'm just an ordinary girl. A girl who knows a bit more about murder cases and forensics that most people. Well, that, and...”

She put her hand under her shirt and pulled something out.

“The God I believe in might be different than yours.”

What she'd taken out was a silver crucifix that hung from her neck. I stared at “that” crucified on the cross.

A silver skeleton, nailed to the cross by the arms and legs, with its head hanging down.

“Tower of Dawn?”

The soft smile on her face instantly turned to a mysterious one. The beautiful silver-haired girl spoke again.

“Allow me to introduce myself properly. My name is Fenrir Alicehazard, and I am one of the Five Archbishops of the religious organization Tower of Dawn.”

“Five Archbishops?”

Dr. Ishikawa tilted his head at her words. However, Sagurioka and I appeared to understand. In Tower of Dawn, there were five Archbishops who served directly under the High Priest who presided over the whole organizations. In other words, at the young age of seventeen, she was already one of the candidates to become the next High Priest of Tower of Dawn.

Fenrir looked down at the corpse of Kanzaki, a priest from the same group.

“I feel sorry for Mr. Kanzaki.” Her eyes lowered mournfully. “But in the last moments of his life, he accomplished something incredible. Look at this perfect locked room.”

Her voice was calm. She sounded proud.

“I've never seen such a perfect locked room before. This scene that claimed Kanzaki's life will surely bring happiness to many others.”

She took out her smartphone and took a picture of Kanzaki's corpse.

Tower of Dawn venerated photos of murder scenes as sacred objects. By dispelling the regrets of the deceased through prayer, the negative energy could be reversed and turned into happiness.

I remembered that was their doctrine.

Even after Fenrir left the scene, the rest of us stared at the walls and carpet in a daze for a spell. Eventually, Sagurioka shook it off and started his investigation. I followed suit.

“I wonder,” Sagurioka said, crouching next to the corpse. “Is there any possibility that this was a suicide?”

I agreed with him.

“What a coincidence. I was just thinking the same thing.”

Because of their beliefs, the members of Tower of Dawn wanted there to be more murders, especially locked room murders. That was why this priest committed suicide in order to falsify one – I thought that was a perfectly valid theory.

But...

“No, suicide is impossible.” Dr. Ishikawa denied us. I asked him about his conclusion.

“What's your basis for saying that?”

“Look at this wound on the corpse,” Dr. Ishikawa said, rolling up the sleeve of Kanzaki's coat. There was a large wound there that looked like a cut from a knife.

“Look at this,” Dr. Ishikawa said. Despite the amount of blood, he was calm, probably because he was used to the sight from his job. “In addition to the stab to the chest, there are multiple other wounds like this. They must have been left by the perpetrator. And this one here was left after Mr. Kanzaki's death.”

“You mean it doesn't show any signs of vital reaction?” asked Sagurioka.

“That's right. This wound hasn't healed at all.”

I nodded as I listened to them.

The human body is designed to naturally close any wounds resulting from injury. The blood will clot and the injury will start to repair. This is called a vital reaction.

However, dead bodies have no vital reactions. If a body is injured after death, the wound won't heal at all. Therefore, by closely examining the wounds on a corpse, it's possible to determine whether they were inflicted pre or postmortem.

“But what I don't understand,” Dr. Ishikawa said, “is why the culprit went out of their way to cut Mr. Kanzaki's arm with the knife after killing him. To be blunt, it was meaningless. Why did they do something like that?”

“You're right,” Sagurioka grunted. “It's a whydunit. Their motive is a mystery.”

But it hit me right away. “No, the reason is simple,” I told them.

“When Dr. Ishikawa saw the wound on his arm, he immediately ruled out the possibility of suicide. What if that itself was the culprit's goal? They injured the corpse's arm to destroy that common locked room solution.”

One of the most disappointing common solutions to a locked room mystery is the victim only pretending to have been murdered when they actually committed suicide. So the criminal removed that option. By wounding the victim's arm after his death, they showed us that this was indeed a murder.

“I see,” Dr. Ishikawa scoffed in amazement. “How thorough. Between that and their copying of the 'House of Snow Locked Room Case', our culprit appears to be quite particular about locked rooms.”

“They sure are a weirdo,” said Sagurioka. “Well, that's why this case is so hard. Oh, right, young man. I knew the answer to that whydunit, of course. I just wanted to give you a chance to prove yourself.”

I'm pretty sure he said “Their motive is a mystery” earlier, but whatever.

“Well, you all do your best,” Dr. Ishikawa said with a shrug. “I'm heading back soon. I've done all I can do. I don't think there's anything else I can do to help a pair of locked room experts like you.”

After saying that, Dr. Ishikawa left. We waved at his back as he went.

“Alright,” Sagurioka said after a stretch. “Time to get serious about solving this locked room.”

I couldn't help but laugh at that.

“Shouldn't we be focusing on finding the culprit and not the locked room?”

“Well, from what I can see, there aren't any clues to the culprit's identity here. Besides, I'm better at howdunits than whodunits.”

I nodded in understanding. Well then, let's see just how good he was.

After that, we spent a while meticulously going over the crime scene. The scene had an identical floor plan as the scene of the “House of Snow Locked Room Case” that occurred in the past, and the layout of the furniture was nearly the same as well. That went for the height of the carpet and the gap under the entrance, too. In fact, even the height of the carpet in the hall was the same.

The items left behind at the scene, too, were the same as in the “House of Snow Locked Room Case”. A small plastic bottle containing a key and a voice recorder with recorded screams loaded in.

I grabbed the small bottle and went out into the hallway. Sagurioka followed me. We shut the door and checked if the bottle could fit under the gap in the door. Of course, it couldn't. The size of the bottle was larger than the size of the gap, so it inevitable got stuck.

“Then it's time for the next step.” Sagurioka took out a length of fishing line. “You came prepared,” I said, impressed. A smile danced on the corners of his lips.

“The reason I originally came here was to solve the mystery of the 'House of Snow Locked Room Case'. Of course I prepared some fishing line. There's no point in idle theorizing if I can't test my hypotheses.”

I nodded. That was true enough.

We spent some time trying out various different theories. We placed the bottle next to the corpse and tried to put the key in it from under the door using fishing line. Then we tried wrapping the fishing line around the lid of the bottle and closing it that way. Both attempts were complete failures. No matter how many times we tried, we couldn't get the key in the bottle, and no matter how we moved the line, we couldn't close the bottle. I tried to think of another approach, but the door was the type that needed the key to lock even from inside the room, like the one at the scene of the “House of Snow Locked Room Case”, so we couldn't use tricks like turning the lock some other way. In other words, the only way to lock the room from the outside was using this key.

Before I knew it, the sun had set, and the scenery out the hallway window was pitch black. We were getting worried. Since the bottle couldn't pass through the gap under the door, the culprit had to have somehow gotten the key into the bottle in the room from outside. It was a truly impossible crime.

“Why did the culprit use a plastic bottle to begin with?” I wondered. Was there any relevance to the bottle being made of plastic instead of glass? Or was it just a coincidence?

“Ah, I see, maybe...”

Sagurioka started to crush and deform the small bottle and tried to pass it under the door that way. I see, I think. Unlike glass, plastic can be deformed. Although it was a simple idea, it could be called a blind spot.

But...

“Hmph.” Sagurioka gave up quickly. The plastic was hard and didn't deform no matter how he crushed it. It looked like it would break if we put too much pressure on it. So that wasn't an option, either.

“Hrrrngh,” I groaned. “What do we do?”

“What's going on over there?”

We heard a voice and turned around. It was Mitsumura. She let out a small sigh.

“I'm shocked. You two are still here?”

Sagurioka and I looked at each other. Yeah, we were still here. Even though it was after sunset.

“It can't be helped,” I said. “We have a mission to solve this locked room mystery, for everyone's sakes. Give us some credit, here.”

“Yes, yes, I'm sure you'll be handsomely rewarded. If you ever actually solve it,” Mitsumura said soothingly. “Besides, it's time for dinner. Everyone else has already gathered in the dining room.”

Sagurioka and I looked at each other. Our stomachs growled.

I really wanted to get dinner, but...

“We'll eat after we solve the mystery,” I said.

“Are you planning on fasting?” she asked in surprise.

“I'll do my best not to starve.”

“When do you expect to be done?”

“As long as it takes.”

“That would cause trouble for Ms. Shihai.”

“We'll solve it.”

“What makes you so sure, huh?”

“Hmm, what should I say.... Ah, how about...”

“Yes?”

“Will you help us out? Help us solve the mystery of this locked room.”

When she heard me, her eyes went wide. “Because...” I continued.

“Don't you think if there's anyone who can solve this locked room mystery, it's you?”

Her wide eyes immediately turned down.

“...What are you saying?” Mitsumura said. “Why would you ask something like that?”

I shrugged my shoulders a bit. Sagurioka chose that moment to interrupt us.

“She's right, what are you saying?” he said. “Stop joking around. This girl, solve this locked room mystery? That's impossible.”

“But she's really smart,” I said. “She even got the top score in a national mock exam, you know.”

“Huh? That was when you were still in middle school, right?”

“It's still impressive.”

“Maybe.”

Our banter complete, Sagurioka let out a small sigh.

“Sure, she's really impressive. Even I've never been able to be the best at a national mock exam,” he said, a smug grin on his face. “But being good at studying and being smart are two different things. I know plenty of people who can study but are completely useless in real life.” 

Isn't that just yourself? I thought. But Mitsumura seemed to take it differently. Despite her cool appearance, she had a surprisingly short temper. Clearly annoyed, she turned to me.

“Just who is this?”

“It's Mr. Sagurioka. You've met several times, haven't you?”

“Ah, that person who was saying all those crazy things when the body was discovered. He was so obviously a useless incompetent that I erased him from my memory. There's no point in remembering someone like him, right?”

Sagurioka's face went red. He must have been easily provoked, as he spoke in a voice full of anger.

“I forgot about you, too. Just now.”

“That's alright, I forgot about you a long time ago.”

“No, I did!”

“No, no, it was me!”

It was like watching a fight between two elementary school kids. It didn't look like a conversation between two intellectuals. ...Is this what they meant by the difference between studying well and actual smarts?

Eventually, Sagurioka started saying things like “Anyway, I'm way smarter than you!”

“Ah, that's it!” he said. “Let's have a competition. Who can solve this locked room mystery first? The loser will have to get down on hands and knees and apologize to the winner. How about it?”

Mitsumura answered him with an arrogant shrug.

“That's fine with me, but is it really okay? That means you'll have to kneel before me.”

“Oh, so confident.”

“Yes, I'm already certain of victory. Because...”

She spoke.

“I have already solved this locked room mystery.”

Those words stopped both my and Sagurioka's thoughts in our skulls. Mitsumura looked at us and tilted her head curiously.

“In fact, I don't understand how you're having trouble with such a third-rate locked room.”

In order to recreate the locked room trick, we went to the room directly below Kanzaki's, the scene of the “House of Snow Locked Room Case”. We'd broken down the door to Kanzaki's room when we found the body, so its lock was broken and the hinges were loose. Mitsumura seemed to want to recreate the trick with the door in as normal a condition as possible. The door to the scene of the “House of Snow Locked Room Case” had also been broken down ten years ago, but it was repaired right after the incident and now it could be opened and closed normally. The floor plan was the same as Kanzaki's room, so it was the perfect place to recreate the trick.

However, Mitsumura, who was the one actually doing the reenactment, was displeased. She seemed to regret that the mystery behind the locked room had been solved.

“What's more, everyone is coming to watch.”

Mitsumura looked around in dismay. As she'd said, almost everyone in the House of Snow was gathered in the room. Sagurioka spoke.

“I thought it would be more exciting if we had an audience.”

He tried to sound innocent, but his intentions were obvious. He probably wanted her to make an incorrect deduction in front of an audience and embarrass herself. Would his wish come true, or...?

Mitsumura sighed.

“Well then, let's get started,” she said, resigned. She looked around at her audience and started at the beginning. “As you all know, in the early hours of this morning, one of the guests at this hotel, Mr. Kanzaki, was murdered. The cause of death was stabbing, and the crime scene was a locked room. What's more, this case is a copycat crime of the 'House of Snow Locked Room Case' that occurred here ten years ago. However, conversely, that means if we can solve the mystery of the 'House of Snow Locked Room Case', we can also solve this mystery. So, we'll be holding an experiment to reproduce the trick here, where the 'House of Snow Locked Room Case' took place. Well, the truth is, we're just using it because the door to the real crime scene is broken... Now then, everyone, please follow me to the adjacent room.”

Following Mitsumura's instructions, we all moved to the next room, where the doll with the knife had been found ten years ago. In that room was the teddy bear acting as the corpse and a knife that had probably been brought from the dining hall. Beside them were a voice recorder and a small bottle containing the room key.

Mitsumura picked up the small bottle, opened the lid, and took out the key from inside.

“When the incident occurred ten years ago, the writers and critics present all declared in unison 'This is a perfect locked room'. I've never read any of Byakuya Yukishiro's works, so I don't know about the incident ten years ago, but I have an acquaintance who is quite knowledgeable about it, and he told me as much.”

Of course, the acquaintance was me. In our free time before the audience gathered in the room, we'd made small talk about the incident.

“But I don't believe that. There is no such thing as a perfect locked room. In fact, this locked room is easy to solve, as there are many clues scattered about. If you unravel the hints one by one, you will naturally find traces of the trick the murderer has set up.”

Mitsumura put the bottle with the key into her pocket. Then, she held up nine fingers.

“There are nine hints in total:

① The voice recorder with recorded screams.

② The window fitted with a lattice.

③ The O-shaped protrusion on the lid of the bottle.

④ The knife stuck in the corpse.

⑤ The gap under the door that is narrower than the bottle.

⑥ The carpet in the hallway with a pile length of 7 cm.

⑦ The pitch-dark room with no lights.

⑧ The room carpet with a pile length of 1 cm.

⑨ The plastic bottle.”

“That's a lot of clues!” Yozuki yelled. “But I don't really see what they mean.”

“Is there any meaning behind the length of the carpet?” asked Fenrir.

“I don't think it means anything that the lights were off in the room,” Riria said.

Mitsumura ran a hand through her long black hair.

“Now, allow me to explain each clue one by one. First, let's start with '① The voice recorder with recorded screams'. Kuzushiro, what do you make of it?”

“Eh, me?”

I was surprised to be called by name all of a sudden. Mitsumura shrugged at me and said “It's easier if you have someone else to listen to your reasoning.” I see, I think. In other words, I'm her assistant.

I decided to live up to her expectations and give my thoughts.

“It was probably to alert people to the presence of the dead body in the room. In other words, the culprit set up the voice recorder to make people discover the dead body.”

Mitsumura nodded.

“Yes, that's it. And the window at the scene is fitted with a lattice, so people can't go in or out through it, so the only way into the room is to break down the door.”

“Which means...”

“Yes, that's it. The culprit set up that voice recorder to force the door to be broken down. Because breaking down the door was the key to creating the locked room.”

After saying that, Mitsumura took the small plastic bottle back out of her pocket.

“Then, next let me explain the O-shaped protrusion on the bottle's lid. This is how it was used.” Then she pulled three meters of elastic cord from her pocket. It appeared to have been made by cutting thick rubber bands, about 5 mm thick, into strings and tying them together. She threaded the elastic cord through the O-shaped protrusion on the lid, approached the latticed window, and knelt down on the carpet on the floor. Then, she passed the end of the rubber cord through the square grid at the point closest to the floor (henceforth “Lattice A”), fed it out the window, then passed the end of the cord through the gap next to it (henceforth “Lattice B”) and back into the room. The rubber cord was wrapped around one of the vertical bars of the lattice. Then Mitsumura took out a thin, bar shaped weight and tied both ends of the elastic cord tightly to it. By tying both ends to the same weight, the rubber cord became a giant rubber ring.

“Next, we hang this bar shaped weight out the window.”

As she'd said, Mitsumura sent the weight out through Lattice B. The room was on the second floor, so it didn't reach the ground, but instead hung out the window via the cord. She then smoothly moved the small plastic bottle, still on the rubber cord, to the opposite end from the weight hanging out the window, that is, as far from the window as the cord would let it go.

Now, the small plastic bottle was fed through one end of a giant ring of rubber cord, and a bar shaped weight was tied to the other, sandwiched against the window lattice. Inside the rubber ring was one vertical bar of the lattice. When Mitsumura tried to pull the rubber ring away from the window, the end got caught on the lattice and the rubber began to stretch.

Mitsumura nodded once, then closed the curtains, just like they'd been when Kanzaki's body was discovered. There was a gap of about a centimeter between the curtain and the floor, so the curtain didn't touch the rubber ring that stretched along the floor.

“Next is ④ The knife stuck in the corpse.”

Mitsumura declared that, then crouched down next to the teddy bear acting as the corpse. She picked up the large kitchen knife with the 30 cm blade, then thrust it into the bear as though she were aiming to pierce through and hit the floor. The teddy bear had been placed right in front of the door connecting the main and adjacent rooms, and the knife pointed towards the door, its edge gleaming.

And on the other side of the teddy bear was the latticed window. The door, bear, and window were perfectly in alignment.

The rubber ring in Mitsumura's hand was caught in the vertical bar of the lattice, stretched nearly into a straight line. It looked less like a ring and more like two strings, holding the knife in the teddy bear. In other words, the knife was surrounded by the rubber ring, like a gigantic ring toss. Then she walked backwards, still holding the small bottle threaded through the edge of the ring.

“I'll leave it like this and go out into the hallway.”

She said that, then she did. The rubber ring caught on the lattice stretched out longer and longer as she moved, and by the time she reached the exit, the rubber ring had tripled in length.

She went out in the hall. Everyone followed her.

The rubber had been stretched taut. In the middle, the line broke as it touched the door frame separating the main room from the adjacent room. To get from the main room to the adjacent room, the actual crime scene, you had to go through the door on the left side of the main room. Therefore, when the elastic cord was stretched from the adjacent room to the main room, in naturally touched the door frame separating the two rooms. Incidentally, the door separating the two rooms had been open at the time of the crime, so we had left it open during our experiment as well.

“I'm going to close the door now.”

Mitsumura closed the door to the room. The stretched rubber cord passed under the gap in the door and followed her out into the hallway. Still holding the rubber cord with one hand, she took out the room key with the other and locked the door.

She turned to the group.

“The door is now locked. I will now place the key in the jar.”

She opened the lid of the bottle, still with the rubber band through it. Then she put the key in the bottle and screwed the lid shut.

“All I have to do now is return the bottle containing this key to the body's side and the locked room will be complete.”

That's was certainly true. But that was the problem. The biggest mystery behind this locked room, of course, was how to get the bottle with the key back inside.

“This is how I'll put it back.”

Mitsumura crouched down by the door and tried to fit the bottle through the gap under the door. But the bottle got stuck on the bottom of the door and wouldn't go through. The sight made Sagurioka burst out laughing.

“Are you kidding me? Just how stupid are you?” He was beyond delighted. “⑤ The gap under the door that is narrower than the bottle. The bottle can't fit under the gap in the door. Forgetting what you yourself just said, you must have the memory of a chicken.”

“It's because I was a chicken in my past life.”

“What?”

“It was a joke. And you're mistaken. I'm not trying to pass the bottle through the gap under the door. I'm taking advantage of the fact that the bottle can't pass through the gap under the door to hook it in place like this.”

With that, Mitsumura let go of the bottle. The bottle was pulled by the tense rubber bands and looked like it was about to fall back into the room. But it didn't. That's because it was stuck in the gap under the door too narrow for it to pass through. It was stuck to the left corner of the door, opposite the hinge.

Mitsumura got down and began stroking the carpet around the door with both hands. She pet it like it was a dog or a cat. “⑥ The carpet in the hallway with a pile length of 7 cm,” she whispered.

“How does it look?”

My eyes nearly popped out. As she'd brushed the long fibers of the carpet towards the door, the bottle hanging on the door had been buried in the fibers, completely covering it. Unless you actually bent down and felt for it, there was no way to tell it was even there.

“The preparations are now complete,” Mitsumura said, standing up. “Well, when we found the body, we broke down the door by ramming it. Hey, Kuzushiro, what do you think would happen if we did the same thing now?”

“What would happen?”

I was confused. Breaking the door in its current state... The door that opened inwards...

Is that how it was? In other words, the locked room trick was...

“Then let's try it out.” Mitsumura bent down by the door again, took out the bottle from the carpet, opened the lid, and took out the key. After unlocking the door again, she put the key back in the bottle. After screwing the lid on tight, she glanced around until her eyes settled on Yozuki.

“Miss Yozuki.” 

“Y-Yes?”

“May I have a little help?”

Mitsumura handed the bottle to Yozuki. Then she pointed towards the door and explained what she needed.

“We're going back inside the room now, but I'd like you, Miss Yozuki, to stay here in the hall and help us recreate the trick. In short, you're my assistant. Specifically, when we enter the room, please hook the bottle back in the gap under the door. Then, when I tell you, throw the door open with great force.”

“Hook the bottle and open the door,” Yozuki muttered, then looked at the bottle in her hand. “Well, I don't mind.”

Mitsumura nodded, then opened the door and invited us back inside. And then Yozuki, who remained in the hallway alone, quietly closed the door behind us. I heard the click of the bottle being inserted back in the gap under the door.

I took another look at the situation inside the room.

The interior of the room was filled with the rubber cord, which stretched out as though it were crawling across the floor. One end of the rubber cord was hooked to the bottle out in the hall, the other end was on one of the vertical bars of the lattice. In between the two was the blade of the knife lodged in the teddy bear.

Mitsumura stopped in front of the door separating the main room from the adjacent room. The door had been left open, just as it was when the body was discovered. Mitsumura moved towards the wall, away from the door, which she never broke eye contact with. Everyone else gathered around her. “Well then...” she said.

“Miss Yozuki, please open the door.”

A second later...

The door opened with force.

Like an arrow in flight, or like a scurrying mouse, the bottle containing the key lost its grip on the door and instantly went flying, pulled by the taut rubber. It ran across the carpet at a blinding speed, making a sharp curve as it flew into the next room. Its momentum sent it flying towards the blade of the knife, causing the rubber ring threaded through its lid to hit the blade. The sharp, 30 cm blade cut through the rubber ring, turning it back into a long rubber cord, which slipped out of the O-shaped protrusion in the bottle's lid. The rubber cord was pulled by the bar shaped weight hanging from the window, slipped through the gap between the floor and the curtain, and disappeared out through the lattice over the second story window.

Only the key in the bottle was left in the room.

Yes... Only the key.

“This is the trick the culprit used,” said Mitsumura. “When we heard the sound of the voice recorder and rushed to the room, the key was still outside. But the moment we broke down the door, the key was pulled into the room by the rubber cord like this.”

We were all shocked speechless. This was the truth behind Kanzaki's murder and the “House of Snow Locked Room Case” ten years ago.

“But isn't that impossible?” It was Sagurioka who asked. He spoke to Mitsumura in a tone that made it clear he just wanted her to give up. “Sure, the rubber band pulled the bottle into the next room in an instant. But even if it took less than a second, wouldn't someone from our group noticed a bottle flying at high speed across the carpet?”

That was true, I thought. Sagurioka's argument was valid. But...

“That is the reason for ⑦.”

“⑦?”

“Yes,⑦ The pitch-dark room with no lights.” Mitsumura said. “When the body was discovered, the lights in the room were off, and the window was covered with a thick blackout curtain like those used in darkrooms, so it was pitch black inside. Furthermore, the two men who broke down the door... Kuzushiro and Mr. Sagurioka, their backs blocked the rest of our views, so the rest of us couldn't see into the room at all. Those who did go into the room went from the lit hallway to the pitch black room. It would have taken a while for their eyes to adjust to the darkness, and since we'd just broken down the door, we weren't concerned with what was right under our feet.”

Sagurioka groaned. Mitsumura finished him off.

“⑧ The room carpet with a pile length of 1 cm. The sound of the bottle moving across the floor was absorbed by the carpet. It's true they couldn't have completely silenced it. But again, we'd just broken down a door. Such a small sound heard immediately after such a loud one would slip completely beneath our notices. In other words, we may as well have not have heard it. And, ⑨...”

Mitsumura looked around to each of us and said:

“The bottle used in the crime was made of plastic. Even if it fell to the floor or hit the wall, it wouldn't break. If it were a glass bottle, it definitely wouldn't have survived this trick... This is the truth behind the locked room. Thank you all for listening.”

“Just who is that kid?”

After Mitsumura finished her deduction, Yozuki asked me that. I shrugged and said “She's just an ordinary girl.” Naturally, Yozuki was unconvinced.

“Is she really?”

“She is.”

 Of course, that was a lie. Well, no, was it? Shitsuri Mitsumura was an ordinary person. She didn't work a special job and she didn't have a special lifestyle.

The only thing about her was... She had a bit of a unique past.

Three winters ago, a girl in her second year of middle school was arrested on suspicion of killing her own father. Given the circumstances, there was no doubt that the girl was the culprit, but at the trial, she was declared not guilty. Why? Because the scene was a locked room.

Three years ago on a winter day, Japan's first locked room murder was committed.

The suspect's name was Shitsuri Mitsumura. The girl who was once my classmate.

 

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